A bird was heard __________in the tree just now.A.singing B.sing C.to sing D.sang
问题描述：
A bird was heard __________in the tree just now.
A.singing B.sing C.to sing D.sang
答
楼上同学的答案我不敢认同 这题当选A
从语法上讲答案只可以是A或者B 又根据本题的时间状语-- just now 所以应该用进行时 所以此题选A
答
很高兴能帮你解答.
答案：C
解析：当hear sb.do/doing sth.用在被动语态时要用to,即sb.be heard to do sth.