重点讲解：
1. be based on 以…为基础；
例句：Early musicwas based onsingle tunes,or melodies.
早期的乐曲是以单一的曲调或旋律为基础的Yb=Dt%gS%T。
2. be made up of 由…组成；
例句：The airis made up ofa mixture of gases.
空气是由多种气体组合而成的7,DX#+6=bZ;~q(d)tg^A。
3. let's say 比如说；比方说；
例句：Another example, you want to be an artist,let's saya painter, but you can't seem to find time to lift a paintbrush.
再比如你想成为艺术家，比方说画家，但是你好像总是没时间拿起画笔|vyqgO.1o_8mw%7q[3CP。
4. build up （使）积聚；（使）逐渐增加；
例句：We have continued tobuild upour capabilities.
我们在持续不断地加强我们的能力i|(w&hMRRHO4==jK-k(*。
5. there's no way 没有可能；
例句：There wasabsolutelyno waythat we were going to be able to retrieve it.
我们绝对不可能把它找回来bjchK4j3TjlP8。