[求助]旧prep2，39

39.       (26492-!-item-!-188;#058&003168)

As it is with traditional pharmacies, on-line drugstores rely on prescriptions to be successful, since it is primarily prescriptions that attract the customers, who then also buy other health-related items.

(A) As it is with traditional pharmacies, on-line drugstores rely on prescriptions to be successful

(B) As with the case of traditional pharmacies, on-line drugstores rely on prescriptions to have success

(C) As is the case with traditional pharmacies, prescriptions are the cornerstone of a successful on-line drugstore

(D) As traditional pharmacies, so on-line drugstores rely on prescriptions to be successful

(E) Like traditional pharmacies, the cornerstone of a successful on-line drugstore is prescriptions

这道题的b项前半部分错了，我没问题。我想问后面的rely on prescriptions to have success是不定式完成形式么？感觉特别怪，又不敢确定不对，不知道有没有这么说的。因为这里不像是不定式完成形式。。。

to have done表过去.

例如, i must have had my lunch.

我一定吃午饭了.

同问一下....

可以说as is the case with 吗?

请教一下这里as 的用法是代词?

as is/was/does etc
formal used to add that what you have said is also true of someone or something else
Eve's very tall, as was her mother. I voted Labour, as did my wife.

找到了,这是词典的解释