1. verb+ it+ adj./noun (for/of) to do/clause (verb=think, believe, suppose, consider, feel, make, keep…)
2. verb+it+adj./noun (one's) doing
(adj.=useless/worth/worthwhile)(noun=no use/no good/worth one's while/a waste of time/money/energy/words
(verb=think, believe, suppose, consider, feel, make, keep…
3. verb+it+ important/unimportant/necessary/unnecessary/natural/essential that … (should)…
4. verb + it+ as+ noun/adj.+ clause (verb=accept, regard, take, see, view)
5. v. +it + prep. + that…
6. It用在不能直接跟宾语从句的动词后面,尤其是表示好恶的动词后,enjoy, like, love, dislike, resent, hate, don't mind, be fond of, feel like, see to 宾语从句紧跟it之后
7. It用在不能直接跟宾语从句的介词后面,宾语从句紧跟it之后(except that例外)