重点讲解：
1. fall off
脱落；掉落；
eg. They fall off their bikes.
他们从自行车上摔下来yxKg1-idE-h。
eg. I saw the boy was about to fall off and caught him just in the nick of time.
我见这男孩快要掉下去，便及时把他抓住了@Cg^%0ob~]@|kq。
2. used to do sth.
过去常常；过去曾做某事；
eg. The old-timers used to recall how hot 1886 was.
老人们常常回想起1886年的酷热.jK_Z~u5AU3d~h-Ra。
eg. I used to write during my free periods at school.
过去我经常在课余时间写作-[d&0B,*iQ;ui9。
3. and so on
及诸如此类；等等；
eg. She spends her day doing housework, watching television, reading, and so on.
她以做家务 、 看电视 、 看书等等度过一天xzyG!Is362D1KmkVJ。
eg. Consumer durables such as refrigerators, television sets, bicycles and so on were produced in large quantities.
冰箱、电视、自行车等耐用消费品被大批量地生产出来%d~W[[7k93IsYdZ+J+zj。