为什么Be busy 和Be Worth 后面要加doing ？

Question

如题所述

Answer 1

不一定。如
be
happy
to
do
be动词后面加
to
do
或doing
有的是固定结构，有的是看具体情况，to
do，将要，doing，正在
be
used
to
doing
be
worth
doing
be
busy
doing
be
seen
doing
be
afraid
of
doing
be
happy
doing
be
good
at
doing
be
to
doing