The best way to make them work hard is to promise them reward.

A. The coffee was very strong, but it couldn’t keep us awake.

B. The coffee was not strong enough to keep us awake.

C. The coffee was not good enough for us to keep awake.

D. We were kept awake although the coffee was not strong.

A. He has been in London for three years.

B. He hasn't visited London for three years.

C. He didn't visit London three years ago.

D. He was in London for three years.

A. It took to get over his illness in three months.

B. It took three months for him to get over his illness.

C. It took him three months to get over his illness.

D. It took three months for his illness to get over.

A. Donald could not stop himself from weeping at the bad news.

B. Donald could not allow himself to sweep at the bad news.

C. Donald could not help himself and so he wept.

D. Donald could not help himself because he was weeping.

A. The referee stopped playing football and blowing his whistle.

B. The referee stopped the football game before he blew his whistle.

C. Having stopped the football match, the referee blew his whistle.

D. The referee brought the football game to a halt by blowing his whistle.

A. Whether the government have established some wildlife reserves or not, endangered species are still protected.

B. Endangered species can't be protected although the government have established some wildlife reserves.

C. The government have established some wildlife reserves so that endangered species can be protected.

D. If the government established some wildlife reserves, they would be able to protect endangered species.

A. My sister is good at cooking, or my brother is bad at it.

B. My sister is good at cooking, for my brother is bad at it.

C. My sister is good at cooking, but my brother is bad at it.

D. My sister is good at cooking, so my brother is bad at it.