這里是不定式的不同時(shí)態(tài)
to be done
to be doing
to do
to have done
to have been done那這倆個(gè)分別是什么時(shí)態(tài)？to be doing 是現(xiàn)在進(jìn)行時(shí)
to do 就是一般現(xiàn)在時(shí)