一、下面每句都有一个标点符号错误，该用标点处未用标点或标点符号用错，改正错误或补写标点。

1.You should sign all letters before mailing them

2.Do you market your product through retailers.

3.The weather was good yet the plane arrived an hour later.

4.The accountant Mr.Price,delivered a long presentation.

5.What a nice girl she is.

答:1.them→them.

2.retailers.→retailers?

3.good→good，

4.accountant→accountant，

5.is.→is!