I don't think it's sensible of you to（）your greater knowledge in front of the chairwoman for it may well offend her.

单项选择题He will simply not listen to anybody; he is （）to argument.

A. impervious
B. imperceptible
C. impassable
D. blunt

单项选择题Because of difficulties in getting a visa, the students had to ______ the idea of applying for study in the United States.