[ Perfect and Past Tenses ]
By the time they reach the summit, they (climb) __________ for six hours.
A. will have been climbing
B. climbed
C. are climbing
Select your answer:

Random Topics:
Articles with SubstancesIntensifiers: Really vs VeryPronounciation and GrammarGrammar: Parts and PunctuationCorrelative Conjunction & Complex SentencesGrammar - Present Perfect Tense3rd Person SingularSo / Neither / Either / TooNouns and QuantifiersConditionals and Modal VerbsOther quiz:
Vocabulary and Grammar › ViewWhat is the meaning of the word ‘diligent’?
A. negligent
B. showing care and conscientiousness
C. careless
D. lazy
Vocabulary › View
a person walking along a road or in a developed area.
A. pedestrian
B. psychological
C. mobility
D. objective
