Joining clauses on ACT English: the three connector types (coordinating conjunctions with a comma, subordinating conjunctions that make a clause dependent, and conjunctive adverbs that need a semicolon), how each is punctuated, and choosing the connector whose logical relationship and punctuation are both correct.

What this skill is asking

Once you can spot independent and dependent clauses, the next skill is joining them with the right connector. The ACT tests three families of connector, and each is punctuated differently: get the punctuation right and the logical relationship right at the same time. Many questions offer the same two clauses with four different connectors, so you choose by meaning; others keep the connector and vary the punctuation, so you choose by rule.

The three connector families

Each family signals a relationship and carries a punctuation rule. Knowing both is the whole skill.

The most common ACT trap mixes the families up, especially using a conjunctive adverb ("however") as if it were a coordinating conjunction. "A, however, B" between two independent clauses is a comma splice; the correct punctuation is "A; however, B."

Choosing by logic

When the four options offer the same clauses with different connectors, grammar will not separate them, so you choose by the logical relationship.

Choosing by rule

When the connector stays the same and only the punctuation changes across options, you choose by the rule for that connector. A coordinating conjunction between independent clauses needs a comma before it; a conjunctive adverb needs a semicolon before and a comma after; a leading subordinate clause needs a comma after it. The punctuation, not the meaning, decides these.

There is also a subtle case: a coordinating conjunction joining a clause to a non-clause does not take a comma. "She trained hard and won the race" has one subject ("She") doing two things ("trained" and "won"), so there is no comma before "and". A comma before "and" is only correct when a full independent clause follows ("She trained hard, and she won the race").

Why this skill ties the structure module together

Joining clauses is where fragments, run-ons, and punctuation meet. A fragment is often a dependent clause that needs to be joined to an independent one; a run-on is two independent clauses that need one of these connectors; and the semicolon and comma rules here are the same ones the punctuation module covers. Master the three connector families and their punctuation, and a large share of Conventions questions, the ones that look like "which connector and comma go here", become a two-step check: right logic, right rule.

Try this

Q1. What punctuation does a conjunctive adverb like "however" take when it joins two independent clauses, and how does that differ from a coordinating conjunction like "but"? [Recall]

• Cue. A conjunctive adverb takes a semicolon before and a comma after: "A; however, B." A coordinating conjunction takes only a comma before: "A, but B." Using a comma before "however" between independent clauses is a comma splice.

Q2. In "The team studied the map and chose the safest route", should there be a comma before "and"? Explain. [Short explanation]

• Cue. No. "And" joins two verbs ("studied" and "chose") that share the single subject "The team", not two independent clauses, so no comma is needed. A comma before "and" would be correct only if a full clause with its own subject followed, such as "...the map, and the guide chose the route."