设函数在上可导，且，则=（ ）。

(单选题)—Have you returned the library book yet?—Not yet. Don’t worr (单选题)My brother usually ______ his clothes on Sundays. (单选题)When his mother came in, the boy pretended ______ a newspape (单选题)Tom often makes his brother ______. (单选题)It is five years since he ______ here. (单选题)My father ______ volleyball with his friends in the gym yest (单选题)—How long have you ______ your bike?—For about two months. (单选题)London is ______ capital of ______ England. (单选题)—What do you do?—______ (单选题)Your brother is ______ to go to school.