[ Grammar ]
Only when ______ may vehicles cross the train tracks.
A. is the green light on
B. did the green light be on
C. on is the green light
D. the green light is on

Random Topics:
Adjectives with PrepositionComparison Degree & GerundsSpeculation with Modal VerbsGerunds, Infinitives and ParticiplesDependent PrepositionsModifiersClauses and ConjunctionUnscramble SentenceDo / Have / Can - Basic QuestionsPresent Progressive or Present SimpleOther quiz:
Future Tenses › ViewChoose the correct option.
Those clouds are really grey! It _______ (rain) very soon.
A. will rain
B. is going to rain
C. is raining
Correlative Conjunction & Complex Sentences › View
Wuhan city now has been running normally …. there was no any new covid19 cases from July.
A. And
B. But
C. Because
D. yet
Grammar › ViewTake care of our environment, _______ that the future generations may also enjoy it.
A. So
B. And
C. But
D. Yet
Modals Verbs › View
We______ have been crazy.
A. Must
B. Will
C. Should
D. Could
