In the Gulf of Mexico the animals' presence close to shore means their usual habitat is badly polluted, and the crowding could ________ mass die-offs as fish run out of oxygen.

Two pages of the original manuscript (底稿) of Albert Einstein's General Theory of Relativity were________  on display in the Israel Pavilion of the 2010 World Expo in Shanghai.
A．put up           B set down            C. sent up                           D. taken up

Keep in mind: your efforts will ______.Don’t let one or two failures over the year get you down.       
A  take off           B. put off           C. pay back             D. pay off

The government _________ the diplomatic (外交的) note from that country for its unclear                 attitude to the trade between two countries.

I’ve _______ to swim last week. But unfortunately I had a bad cold and therefore couldn’t go.

Our classmates _________ the losing team of our class and our team won the game at last. 

His son __________ the old man with all the food and the money he needed.

The doctor said jokingly that his own infection of the virus _______ the discovery of a vaccine (疫苗)of the disease.

31. The engine of the bus was out of order and the bad weather ______ the worries of the passengers.

-- Why didn't Mike attend the evening party?
-- He is a quiet boy; He loves reading at home ______ to parties.