The cover letter will be seen first. ________, it must be very well written.

选择一项：
A. Therefore
B. Besides
C. However

A. Therefore译文：附函是首先被别人看到的。所以必须要好好写。 解析：正因为投递简历时附函是首先别看到的，所以才要好好写，用therefore （因此，所以）符合逻辑关系，所以正确答案选Therefore。