We were having breakfast when I heard the telephone _____(ring).ringto be ringto be ringing这三个填法有何不同,
问题描述：
We were having breakfast when I heard the telephone _____(ring).
ring
to be ring
to be ringing
这三个填法有何不同,
答
ringing,前面用的是过去进行时，后面表示我们正在吃饭的时候听见电话响了，应该也用进行时。hear sb do sth 或hear sb doing sth.
答
ring
答
答案ring
解析：hear sb.+ do 或doing
没有hear sb.do to结构