英文文法..請幫我解釋...謝謝 - 社會議題

做題目愈到一些不會文法不會的問題,請會的人幫我解釋
1. The ECO is now faced with a decision whether to downsize the
current operations or lay _____ 500 employs. 答案是(C)

(A) addition
(B) an addition of
(C) an additional
(D) in addition


2. Paul is a man _____ I believe has the best understanding of what it
is thatmakes our product different from others on the maket.
答案是(A)........這題是受詞,不是應該是B嗎???
(A) who
(B) whom
(C) whose
(D) how
3. By teaming up, we finally solved the thorny problem that might __
___ never have been solved by one person alone. 答案是(D)
(A) solely
(B) fully
(C) further
(D) otherwise
4. A few days ago that newspaper ran an editorial which spoke_____
of those who took the issue of global warming seriously.
答案是(B)
(A) widely
(B) highly
(C) deeply
(D) broadly