[ 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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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
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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