最佳接收的背景条件是（）。
A.加性干扰
B.乘性干扰
C.码间干扰
D.白噪声
参考答案：D
阅读课文Unit6《I love learning English》回答下列问题。
1. How do you say the word at first?
___________________________
2. Who do you need to talk to?
3. What can your teacher help you do？
4. Is the word "understand"a noun or a verb?
“狠”，就是要给犯罪分子以严厉打击，加重对其惩罚。( )
