hear后加动词什么时态

1.听到,听见,hear sth.+vt.及物动词.如：I heard a strange voice just now.
2.hear of听说.如：I heard of him before.
hear from 收到某人来信.如：I am glad to hear from you.
3.hear sb do sth 听到某人做某事 .如:I heard Tom sing yesterday.
4.hear sb doing sth 听到某人正在做某事如：I heard Tom singing in the classroom when I came in yesterday.
5.hear +that 从句.如：I heard that Liu Dong had passed the exam.

hear + 动词原形 表示听见的这个动作已经完成
hear + 现在分词 表示听见的动作正在进行
都可以，根据情况选择

hear doing sth

hear sb to do sth是听到某人做某事,听到全过程
hear sb doing sth是听到某人正在做某事，是一瞬间的

hear sb do sth听见某人做了某事,
hear sb doing sth听见某人在做某事