A seesaw can be turned into a ramp by placing blocks on one end, for example.
A seesaw can be turned into a ramp by placing blocks on one end, for example.
打个比方，如果将秋千板拉到某一方，它就可以荡起来。
A seesaw can be turned into a ramp by placing blocks on one end, for example.
打个比方，如果将秋千板拉到某一方，它就可以荡起来。