before doing sth还是do sth
before doing sth还是do sth
before sb doing还是do sth
help,open的过去分词是什么?是before sb do sth.还是before sb doing sth...
use sth doing sth还是use sth to do sth
before doing sth 和 before you do sth,为什么?
plan+to do sth.还是doing sth.还是 do sth.
expect to do sth还是doing sth?
have somebody do sth 还是doing sth?
after do sth.还是after doing sth.
mind doing sth还是 to do sth
important do sth 还是,important doing sth
never doing sth 还是do sth?