[ Grammar ]
What type of sign does this pic belongs to?
A. Permission
B. Obligation
C. Prohibition
D. Allowance

Random Topics:
InfinitivesAuxiliaries VerbLanguage Features: Reflective ArticleVerbs + Infinitives / Gerundsused to vs be used to vs get used toWish clauseWill or Going toPronouns and AntecedentsPast and Past ContinuousActive and PassiveOther quiz:
Modal Verbs › ViewIn this school we have a rule: students (use) their mobile phones.
A. have to
B. shouldn’t
C. must
D. mustn’t
Grammar › View
Dogs _____ as pets for centuries.
A. Were kept
B. Are kept
C. Have kept
D. Have been kept
I _________ sleep last night.
A. can’t
B. couldn’t
C. won’t be able to
D. shouldn’t
Vocabulary › View
(adj) not clear; uncertain
A. definite
B. doubtful
C. reliable
D. vivid