Driving on the highway be very dangerous, so you be too careful.
A. should; ought to
B. could; should
C. might; mustn’t
D. can; can’t
网友回答
A. should; ought to
B. could; should
C. might; mustn’t
(答案→)D. can; can’t
解析：考查情态动词。在高速公路上驾车是很危险的，所以你越小心越好。Can’t … too..越……越……，选D。