Since 2008, China__________ a powerful high-speed railway network.
A.develop B.developed C.has developed D.will develop
Supercomputers are thousands of times__________ than ordinary computers.
A.fast B.faster C.fastest D.the fastest
I did well in the sports meeting this term__________ I trained hard.
A.because B.so C.when D.if
— Linda, __________ you take care of your little sister this afternoon?
— Sure, Mom!
A.must B.need C.can D.should
—__________ do you usually have a haircut, Jim?
— Every three weeks. My hair grows so fast.
A.How much B.How many C.How long D.How often
We need to finish writing a book review__________ English this weekend.
A.in B.at C.off D.by
