41. It takes sb some time/money to do sth . 花费某人多长时间做某事（常考）
42. pay …for… cost spend…on….. it take …to do sth
43. It's best for sb to do sth. 对某人来说做某事是最好的
had better do sth 最好做某事（注意had没有时态和人称的变化，better后接动词原形）
44. It's time for sb to do sth 是某人做某事的时候了
45. keep (on)doing sth 坚持做某事（常考）
keep sb doing sth 让某人做某事（常考）
keep sb from doing sth 阻止某人做某事（常考）
keep sb/sth +adj
keep the book for 2 days 借这本书两天（不要用borrow或lend）
46. learn to do sth 学做某事
learn sth from sb 向某人学习
47. like to do/doing sth 喜欢做某事
like sb to do sth 喜欢某人做某事
48. need to do sth 需要做某事
need doing sth/to be done
need sth needn't do sth
49. prefer to do sth rather than do sth 宁愿……而不愿……（常考）
prefer doing sth to doing sth 喜欢做……胜过做……
I prefer reading books to going shopping. 比起购物来，我更爱读书。
prefer to do sth 喜欢（爱）做某事