16种,常用9种
常用的：
一般现在时 do/does
一般过去时 did
一般将来时 will do/be going to do...
过去将来时 would/shoud do
现在进行时 be doing
过去进行时 was/were doing
现在完成时 have/has done
过去完成时 had done
现在完成进行时 have/has been doing
不常用的：
将来进行时 will/shall be doing
过去将来进行时 would/should be doing
将来完成时 will/shall have done
过去将来完成时 would/should have done
过去完成进行时 had been doing
将来完成进行时 will/shall have been doing
过去将来完成进行时 would/should bave been doing