Question

英语时态当时间状语是什么时用完成时？一下全忘了

Answer 1

当时间状语是
for
+一段时间
since
+时间点
时
可以用完成时

如
he
has
studied
english
for
three
years

he
has
studied
english since
three
years
ago.

另外
in
the
past/last
few
years
,
before,等
也是用现在完成时