在每小题列出的四个备选项中只有一个是符合题目要求的，请将其代码填写在题后的括号内。错选、多选或未选均无分。

1.In our letter of May 10, we make ______ clear that shipment be effected in June. （　　　）

A. you                                     B. them

C. us                                                   D. it

2.As said in the email today, we are forwarding you under separate cover the samples, ______you will find them satisfactory. （　　　）

A. hope                                                    B. to hope

C. hoping                                               D. hopefully

3.Letters of complaint should be written with care and tact ______to harm future business relationships. （　　　）

A. in order                                      B. in not order

C. in order not                                       D. not in order

4.Our products are of better quality than ______ from other sources. （　　　）

A. that                                           B. this

C. them                                    D. those

5.We are unable to offer firm, as the goods are of ______supply. （　　　）