用括号内所给动词的适当形式填空，并将答案写在答题卡标有题号的横线上。Many great changes ____________ (take) place in China during the past 10 years.
We should think about all we can do ____________ (prevent) animals and plants from becoming endangered.
Today, to hold the Olympic Games ______________ (consider) as a rich prize for a country.
The engineers ____________ (search) for some information on the Internet in the laboratory when Mr. White arrived.
Jack and Susan ____________ (know) each other since they were children, so nobody was surprised to hear that they got married.
He promised that he ___________ (not forget) to hand in his report before weekend.
The patient jumped excitedly when he heard his illness could ______________ (cure).
We should try out best to stop those factories ____________ (pollute) the rivers again.