[ Tenses ]
When he ___________________ (found) Microsoft, Bill Gates was only 20 years old.
A. found
B. founded
C. had found
D. had founded

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Progressive Perfect and Simple Verb Tenses › ViewI WILL BE PHOTOGRAPHING every animal I see at the zoo today.
A. present progressive
B. past progressive
C. future progressive
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serene
A. able to be touched or felt
B. a natural ability to do something
C. calm, peaceful, untroubled
D. absolutely necessary or important; essential
Grammar › ViewThe equipment I have ordered for the science lab _________ of five beakers, eleven test tubes and ten weighing scales.
A. consists
B. consist
C. is consisting
D. are consisting
Grammar › View
Today is holiday and these places of interest are open for free, so you _____ pay to get in.
A. mustn’t
B. mightn’t
C. shouldn’t
D. needn’t