1. The book says China sent one hundred twenty boys to America to learn about developments that could help modernize their country.
learn about 了解
例句:Childrenseem to learn about computers by osmosis.
儿童似乎不知不觉地就了解了计算机.
2. And we came across this very arresting photograph of a young Chinese boy dressed in what appeared to be traditional Chinese dress.
come across 碰到
例句:If they come across a foreigner, they will combine.
如果碰到一个外国人,他们就会联合起来。
3. Mr. Leibovitz said he was lucky to have so much information from events that took place long ago.
take place 发生
例句:Earthquakes take place far underground.
地震则发生在地球的极深处。
4. They no longer spoke Mandarin well enough to answer questions.
no longer 不再
例句:He has that prominence no longer.
他不再拥有那种卓越的地位。