Like compares to a noun. As compares to a clause that has a verb. She writes like a coach. She writes as a coach would. Diction items like this are in word choice on ACT English.
Noun or clause
If what follows is just a person, a thing, or a phrase with no verb, use like. If what follows has its own subject and verb, use as or as if. He timed the section like he was running a race is the trap. The clause has a verb, so it wants as if.
Comparisons that use than rather than like are in then versus than and comparison words.
The bottom line
No verb after it: like. A full clause after it: as or as if. The grammar map is in ACT grammar rules.
Start practicing
Start with a free diagnostic, then drill your weak spots with 15-question quizzes and track how you're doing across Reading, English, and Math. Compare plans whenever you're ready to go further.
This article offers general ACT prep guidance. The ACT can change from year to year, including its format, scoring, policies, test dates, and fees, so always confirm the latest details on the official ACT website at act.org before you make decisions. ACT® is a registered trademark of ACT, Inc. thirty-six is not affiliated with, endorsed by, or sponsored by ACT.