Khi nào thì một lớp bán dẫn p kẹp giữa hai lớp bán dẫn n trên một đơn tinh thể được xem là một tranzito n-p-n?

Mark the letter A, B, C or D on your answer sheet to indicate the word(s) CLOSEST in meaning to the underlined word(s) in each of the following questions.

It’s a really difficult matter to decide how to solve now. I will need time to think it twice

A. to think it over

B. to make it better

C. to make up for it

D. to think out of time