问题补充：
---Please us in the discussion.
---Id like to, but Im busy at the moment.
A. join in; much too
B. join; far too
C. take part in; rather too
D. play a part in; too much
答案：
A. join in; much too
(答案→)B. join; far too
C. take part in; rather too
D. play a part in; too much
解析：词义辨析。Join sb 加入某人，和某人一起做某事；join in=take part in 参加…活动；far是用来加强too的语气的，too修饰形容词busy.结合句意可知B正确。句意：—请和我们一起讨论这个问题。—我想的。可是我现在太忙了。
