We could hear birds ________in my hometown in the past, _________ now we can’t.
A.to sing; and | B.sing; and |
C.to singing; because | D.sing; but |
We could hear birds ________in my hometown in the past, _________ now we can’t.
A.to sing; and | B.sing; and |
C.to singing; because | D.sing; but |