-- What has a pouch?
--
A:Kangaroo.
B:Donkey.
C:Lion.
D:Tiger.
如图所示,物块A放在直角三角形斜面体B上面,B放在弹簧上面并紧挨着竖直墙壁,初始时A,B静止;现用力F沿斜面向上推A,但A,B仍未动.则施力F后,下列说法不正确的是( )
I was unhappy because I ______ my wallet.
下列运算正确的是( )