重点讲解：
1. blow up 引爆；（使）炸毁；（使）爆炸；
Their boat blew up as they slept.
他们睡觉的时候船爆炸了。
2. touch down 降落；着陆；
The shuttle is pulled away from the International Space Station and is expected to touch down on Wednesday.
该航空飞机驶离国际空间站，预计将于星期三着陆。
3. speed up 加快(…的)速度；
The new measures will speed up the registration process.
这些新措施将加快注册过程。
4. engage in 参与；从事；
They have engaged in trade for many years.
他们经商已多年。