I haven’t heard a letter from him since he left 请问这题为什么错了，答案是I haven’t got a letter from him since he left

备注(1)：收到某人的来信只能有以下几种表达

【1】hear from sb 收到某人的来信

 It's always great to hear from you能收到你的信总是让人很高兴。

【2】receive a letter from sb=receive one’s letter 收到某人的信。

Tom received a letter from me yesterday.

=Tom received my letter yesterday. 汤姆昨天收到我的信。

【3】get a letter from sb 收到某人的信

 I get a letter from my former student.  有时我会收到以前学生寄来的信.

备注(2):hear 听见/听到 后面只能接表示“声音的名词/听见内容/某人的声音”

She heard footsteps behind her.她听到背后有脚步声。

Didn't you hear what I said?难道你没有听到我的话？

She heard no further sounds.她再没有听到别的声音了。

The trumpet can be heard all over their house.喇叭声整栋房子都能听见。