（一）
"Can I help you?"
"Thanks, but I'm already ____ "
A. helped
B. being helped
C. having helped
D. helping
答案是B，但我想問A為何不行？
查被動式只有「be + p.p.」，好像A也是合文法的？
（二）
If you are interested in knowing more, then it is pobably best to use the
sales __(3)__ form to kick things off.
A. enquiring
B. enquire
C. enquiry
D. enquirer
我想 enquiry form 是名詞+名詞的用法，
不過前面的sales在這裡是什麼意思呢？

A is semantically odd.

I’m helped.總是有人幫我。I’m being helped.現在有人幫我。

sales enquiry form是買方寫給銷售部門的諮詢表格直接google"sales enquiry form"可知長什麼樣子。