1.John plays football ________， if not better than, David.
A．as well B．as well as
C．so well D．so well as
答案 B [把if not better than去掉答案就一目了然了，as well as是“和……一样好”，而so well as一般不用于肯定句中。]
2．She opened the envelope, ________ the letter and began to read it.
A．unfolded B．folding
C．unfolding D．folded
答案 A [这是三个连续发生的动作。若选C则表示open the envelope与unfold the letter动作是同时进行的，显然不合逻辑。]
