幾個TOEIC閱讀的問題 - 自學

大家好
小弟正在準備TOEIC考試(2/11那場)
有幾題搞不太懂
想請問大家(不知這樣有沒有違反版規?)
1．By the end of this year, economic and political situations ___ greatly
(A) will be changed (B) will have changed (C) changes (D) changed
答案是B，想知道為什麼不能選A

2．There have been no grievance ____ problems reported in the last six months
(A) or (B) but (C) and (D) also
答案是A，想知道為什麼不能選C

3．挑錯：Today, the stock market surged to it's third record high and gained 200 points for the week
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答案是第三個，不知道錯在那裡...

煩請各位解答了，謝謝

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