Choose the correct option to complete the sentence.
Context: Your roommate left a note on the fridge this morning.
Please remember ___ the electricity bill today — it's due at midnight!
The correct answer is to pay.
Remember + to-infinitive means "don't forget to do something" (a future task). The bill hasn't been paid yet, so this is a reminder about a duty. "Remember paying" would mean recalling a past payment you already made.
Gerund
A gerund is the -ing form of a verb used as a noun — swimming, reading, being late. It can sit in any position a noun can: as the subject (Swimming is fun), as the object of a verb (I enjoy swimming), or as the complement of a preposition (She's good at swimming).
Gerunds matter because dozens of common English verbs and almost every preposition force you into the -ing form. Pick the wrong shape — I enjoy to swim, good at to swim — and the sentence sounds clearly off to a native speaker. Knowing which contexts demand a gerund (vs. an infinitive) is what makes verb patterns click.
Infinitive
The infinitive is the basic, unmarked form of a verb, used when no tense or subject agreement is needed. English has two flavours: the to-infinitive (to swim, to read) and the bare infinitive (swim, read). The to-infinitive follows verbs like want, decide, hope, plan (I want to swim); the bare infinitive follows modal verbs (I can swim) and certain causative verbs (Let him go).
Knowing which form to use after which verb is one of the trickiest distinctions in English — closely tied to the parallel choice of gerund (-ing form). I want to swim but I enjoy swimming aren't interchangeable.
Verb
A verb is a word that expresses an action, a state, or an occurrence — the engine of every English sentence. Most verbs have five forms: base (go), -s form (goes), past tense (went), past participle (gone), and -ing form (going). The verb be is the major exception with eight forms; modal verbs like can and must have fewer.
Verbs carry tense (when), aspect (how it unfolds), mood (the speaker's attitude), and voice (active vs passive). Mastering them is foundational — virtually every other grammar topic depends on getting verbs right.
B1 | Intermediate
B1 is the intermediate level in the CEFR framework — the point where you stop relying on memorised phrases and start handling everyday English independently. At B1 you can describe experiences, explain opinions, and follow most clear standard speech on familiar topics like work, travel, and hobbies.
Grammatically, B1 means combining tenses with precision, building complex sentences, and starting to use passive voice, modal verbs for necessity and possibility, and verb patterns (gerund vs. infinitive). Knowing your level shapes what you study next: pushing too far ahead frustrates you; staying below your level wastes time.
Difficulty: Medium
The Medium difficulty tag marks questions and challenges in the middle of the difficulty range — typically suitable for A2 to B1 learners. Expect a single rule with realistic distractors, longer sentences, and contexts where you have to think before answering rather than reading off the obvious choice.
Filter by Medium when you're past the absolute basics and ready to consolidate. It's the level where most lasting progress happens — easy enough that you can finish without exhausting concentration, hard enough that getting it right means you've actually understood.