It may not be a good habit to look up the dictionary whenever you ___

单选题It may not be a good habit to look up the dictionary whenever you __________ a difficult word while reading．

A．come at
B．come across
C．come along
D．come up

【参考译文】在读书的时候碰到任何难单词都去查词典可不是一个好习惯。
【答案解析】本题考查come的词组辨析。come at，达到，弄清楚；come across，遇到，碰到；come along，一起走，随之而来；come up，上升。句中的意思是指遇到生单词，所以答案选B。

1I __________ reading newspapers during breakfast．

A．am in the habit of
B．make a rule of
C．ought to
D．used to be

2 __________ emergency,it is advisable to remain calm and do not panic．

A．Because of
B．In case of
C．By means of
D．In spite of

3The public __________ the officials of neglecting their duty．

A．ashamed
B．related
C．blamed
D．reflected