邮政储蓄档案的保管期只分为永久、25年、10年、5年、3年。
参考答案:错
— I left my keys in the room yesterday. I had to get in _____ the window.
— It's dangerous to do that. [ ]
A. in
B. through
C. over
D. to
请你举出两个把“动能和势能的转化”的知识应用在生活中的例子:
(1)______;
(2)______.