be behind in doing sth
be interested in doing sth
be long in doing sth
be busy in doing sth
be sophisticated in doing sth
be successful in (doing) sth.be successful at (doing) sth.
be absorbed in(doing)sth
用be slow in doing sth造句
be active in (doing) sth怎样造句
be worth doing sth .doing前面加in么?
be interested in doing和be interested in sb/sth
是be interest in doing sth还是be interested in doing sth
be excited in doing sth?be excited about doing sth?区别