Free HESI A2 Grammar guide
October 2026 - Simple, Compound & Complex Sentences Study Guide for nursing students in
A simple sentence has one independent clause. A compound sentence joins two with a coordinating conjunction. A complex sentence attaches a dependent clause to an independent one. Counting clauses and checking what joins them identifies any sentence in seconds.
The four sentence types
| Type | Structure | Example |
|---|---|---|
| Simple | One independent clause | The nurse checked the chart. |
| Compound | Two independent clauses joined | The nurse checked the chart, and the doctor reviewed the notes. |
| Complex | One independent plus one dependent | Because the chart was incomplete, the nurse called the ward. |
| Compound-complex | Two independent plus at least one dependent | Because the chart was incomplete, the nurse called the ward, and the doctor waited. |
A simple sentence is not necessarily short. The senior nurse on the evening shift carefully checked every chart on the ward before handover. has one clause and a great many words — length and structure are different things, and questions rely on the assumption that they are the same.
How to identify one in a hurry
- Count the subject-verb pairs. One pair means simple.
- For two or more, check what joins them: a coordinating conjunction makes it compound.
- If a clause opens with because, although, when, if, since or while, it is dependent — so the sentence is complex.
- A compound subject or a compound verb does not create a second clause.
The nurse and the doctor reviewed the notes.is still simple.
The punctuation that goes with each
A compound sentence takes a comma before the coordinating conjunction: The ward was busy, but the handover ran on time. The seven coordinating conjunctions are for, and, nor, but, or, yet and so.
A complex sentence takes a comma when the dependent clause comes first — Because the ward was busy, handover ran late — and usually no comma when it comes second: Handover ran late because the ward was busy. That asymmetry is directly tested.
Classifying a sentence
Worked example
Classify: When the results arrived, the consultant reviewed them and the team met to discuss the plan.
- Find the clauses: "when the results arrived", "the consultant reviewed them", "the team met to discuss the plan".
- Test each for independence. The first opens with "when", so it is dependent. The other two can stand alone.
- So there are two independent clauses and one dependent clause.
- Two independent plus a dependent is compound-complex.
Compound-complex. Counting the clauses first and testing each for independence is quicker and more reliable than trying to recognise the shape whole.
Terms to know
- Simple sentence
- One independent clause.
- Compound sentence
- Two independent clauses joined by a coordinating conjunction or semicolon.
- Complex sentence
- An independent clause with a dependent clause attached.
- Compound-complex
- Two or more independent clauses plus at least one dependent clause.
- Coordinating conjunction
- for, and, nor, but, or, yet, so.
- Subordinating conjunction
- because, although, when, if, since, while, after, unless.
- Compound subject
- Two subjects sharing one verb. Does not create a second clause.
What the HESI asks most
The same core ideas appear in different wording. If you can answer these without stopping to think, you have what this section requires.
What type of sentence is this?
Count the clauses, then check whether each can stand alone.
Which of these is a compound sentence?
Two clauses that could each be a sentence, joined by one of the seven coordinating conjunctions.
Where should the comma go?
Before the conjunction in a compound sentence; after a dependent clause that comes first.
Key points
- Simple is one independent clause, however long.
- Compound is two independent clauses joined by a coordinating conjunction or semicolon.
- Complex is one independent plus one dependent clause.
- A compound subject or verb does not make a compound sentence.
- Comma before the conjunction in a compound; comma after a leading dependent clause.
Review quiz
4 questions on this topic, each with the reasoning worked through. Pick an answer to see how it went, or open the explanation straight away.
-
Question 1 of 4
Which of the following is a compound sentence?
Show the answer and explanation
Correct answer: C. The nurse completed the round, and the assistant updated the notes.
Two clauses that could each stand alone, joined by "and" with a comma before it. The first has a compound subject but only one clause, the second is complex because "after" makes the opening clause dependent, and the fourth is a fragment.
-
Question 2 of 4
What type of sentence is:
Although the ward was full, every patient was seen within the hour.?Show the answer and explanation
Correct answer: C. Complex
"Although the ward was full" cannot stand alone, so it is dependent, and it is attached to one independent clause — the definition of complex. A compound sentence would need two clauses that could each stand alone.
-
Question 3 of 4
Which sentence is punctuated correctly?
Show the answer and explanation
Correct answer: B. The results were delayed, but the treatment began on time.
A compound sentence takes the comma immediately before the coordinating conjunction. The first omits it, the third places it after the conjunction, and the fourth separates a subject from its verb.
-
Question 4 of 4
Why is
The senior nurse and the ward manager reviewed every chart before the audit.a simple sentence?Show the answer and explanation
Correct answer: B. Because it contains only one independent clause, despite having a compound subject.
Two people share a single verb, which gives a compound subject but still only one subject-verb pair, so one clause. Length is irrelevant, the sentence does contain "and", and lacking a dependent clause only rules out complex — it does not by itself make a sentence simple rather than compound.
Put this HESI topic into practice
Build a set on compound and simple sentences and use the rationale on every question to reinforce what you just reviewed.
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