Drag the correct words to fix this journal entry. One sentence has a mistake!
Context: Tom is writing about his progress with a new fitness routine.
"Week 1: It's hard to exercise every day. ❌ Week 4: I'm finally good at to run long distances! Wait… that doesn't look right."
Help Tom correct his mistake:
"I'm finally good at running long distances!"
The correct answer is running.
After the preposition at (in "good at"), use a gerund (-ing form), not a to-infinitive. "Good at to run" is incorrect!
Gerund
If you've ever said I enjoy to read or good at to swim and wondered why it sounded wrong, you've met the gerund. English is fussy about which structures take -ing and which take to + verb, and getting this wrong is one of the most common giveaways that someone learned grammar from a list rather than from real usage.
A gerund is the -ing form of a verb acting as a noun — reading, swimming, being late. After many common verbs (enjoy, avoid, finish) and after every preposition, English demands the gerund, never the infinitive.
Infinitive
If you've ever written I enjoy to swim or He let me to go and only later learned why both are wrong — you've hit the infinitive's main puzzle. English is fussy: some verbs demand the to-infinitive, some demand the bare infinitive, some demand the gerund, and a few accept multiple options with different meanings (remember to lock vs remember locking).
The infinitive is the basic form of a verb, used non-finitely. The to-infinitive (to go) follows verbs like want, decide, plan; the bare infinitive (go) follows modal verbs (can, will) and causatives (Let him go).
Verb
If grammar feels overwhelming, the fix is almost always to focus on verbs first. They carry the action, the time, the mood, and the voice — a single verb form decides whether your sentence reads as past or present, fact or hypothetical, active or passive. Get verbs solid and the rest of grammar suddenly looks much smaller.
A verb expresses action, state, or occurrence — the engine of every English sentence. Most verbs have five forms (base, -s, past tense, past participle, -ing); be has eight; modal verbs have fewer. Verbs carry tense, aspect, mood, and voice.
B1 | Intermediate
If you can hold a conversation about your weekend, explain why you're late, and follow a short news story without panicking — but still feel lost in fast or technical English — you're probably operating at B1. Knowing this matters: study material at the wrong level either bores you or burns you out, and B1 is the typical target for travel, casual work, and most everyday social English.
B1 is the intermediate level in the CEFR framework, where you handle everyday English independently and start combining ideas with complex sentences, passive voice, and modal verbs.
Difficulty: Medium
If easy questions feel too obvious but hard questions leave you guessing, you're probably ready for Medium — the level where most real learning happens. It pushes just enough to expose the rules you don't quite have yet, without burying you in edge cases. This is where steady fluency is built, one well-aimed challenge at a time.
The Medium difficulty tag marks middle-range challenges — typically A2 to B1. One rule per question, realistic distractors, and contexts that require active thought rather than instant recognition.