The correct answer is to go.
Error: decide + gerund ā Correct: decide + to-infinitive. The verb "decide" must be followed by the infinitive form. Always say "decided to go," never "decided going."
Gerund
Gerund vs infinitive: the biggest source of errors for non-native speakers. Some verbs take only gerund (enjoy reading ā ), some only infinitive (want to read ā ), some take both with different meanings (stop reading ā stop to read). There's no logical rule ā these must be learned by verb.
A gerund is the -ing verb form used as a noun. After prepositions = always gerund. After certain verbs (enjoy, avoid, finish) = always gerund. After to (preposition, not infinitive marker) = gerund (I look forward to seeing you).
Diagnostic: can you replace the -ing word with "it" or "something"? I enjoy it ā yes, it's acting as a noun = gerund.
Infinitive
Infinitive vs gerund: the #1 verb-pattern confusion. Some verbs take only infinitive (want to go ā ), some only gerund (enjoy going ā ), some both with different meanings (stop to smoke ā stop smoking). No logical rule exists ā learn by verb.
The infinitive = base verb form used non-finitely. To-infinitive (to go) after certain verbs. Bare infinitive (go) after modals and causatives.
Diagnostic: what's the main verb? Check whether it takes to-infinitive, bare infinitive, or gerund. If unsure, try both and see which sounds natural to native speakers.
Verb
Verb vs noun vs adjective: nouns name things. Adjectives describe. Verbs express what happens or what IS. The test: can it take tense (walked, will walk)? Can it take -ing? Can it follow to as an infinitive (to walk)? Yes to any ā verb. English often converts freely between classes (run = noun or verb), so context decides.
A verb = action/state/occurrence word. 5 forms (base, -s, past, past participle, -ing). Carries tense, aspect, mood, voice. The one required element in every sentence.
Diagnostic: does it change for tense (walk ā walked)? Can you put to before it (to walk)? Does it take -ing (walking)? ā verb.
B1 | Intermediate
B1 vs B2: B1 handles standard everyday communication and simple opinions. B2 handles abstract topics, sustained arguments, and nuanced register. If you can chat about your life but struggle to debate an issue or write a formal essay, you're B1.
B1 is the intermediate CEFR level: independent handling of familiar topics, second conditional, basic passive, reported speech, and linking words for cause and contrast.
Diagnostic: can you read a newspaper article on a familiar topic and summarise the argument? Comfortably ā B2. Struggle with abstractions ā still B1.
Easy
Easy vs Medium vs Hard: Easy = one rule, obvious answer, A1āA2. Medium = one rule but realistic distractors, A2āB1. Hard = interacting rules, edge cases, B2+. Start Easy to check you have the basics before moving up.
The Easy tag filters for single-rule, short-sentence, common-vocabulary challenges designed for beginners or for anyone wanting a confidence check on fundamentals.
Diagnostic: if you get Easy questions wrong, stay here ā your foundations need work. If they feel trivial, move to Medium.