1.a.( if ...had +done/been ,...would have done/been )
2.c.( did+ future time/ were,...would do/be )
3.b.c 都对.肯定是备选答案给错了.
4.b.
1.a.( if ...had +done/been ,...would have done/been )
2.c.( did+ future time/ were,...would do/be )
3.b.c 都对.肯定是备选答案给错了.
4.b.