In order to _______ the problem， we need to study a lot more

仔细阅读下面五个句子，然后用下面方框中所给的单词或短语填空，使每个句子在结构、句意和逻辑上正确。（提示：选项中有一个是多余的。）
　　46. In order to _______ the problem， we need to study a lot more.
　　47. The room is quite quiet， but there is a fly _______ against the glass.
　　48. In fact， Mary spends a lot of time waiting for parents who don’t _______.
　　49. Why not try this red dress？ You’d look good in red and other _______ colors.
　　50. Miss Kim was not sure of the meaning of his words， so she chose to remain _______.
　　46. _________ 47. _________ 48. _________ 49. _________ 50. _________