回上一层第八部 第七课 --- 请重复跟读，直到可以於声音档的留空之间唸完整句為止；熟练之后您必将可以 "脱口而出" 地说出标準的美式英语
- not to mention
- You can't even fry an egg, not to mention a fish.
- now and then
- The refrigerator breaks down every now and then.
- on and off
- Danielle went to school on and off during her childhood.
- It has been raining on and off since noon.
- on and on
- Dawn kept chatting on the phone on and on.
