A:H2SO4
B:熔融的MgCl2
C:NaCl溶液
D:蔗糖
当自行车下坡时,即使不蹬车,自行车的速度也会越来越快,这是因为自行车受到____ 的作用,用力捏车闸,自行车的速度会减慢,这是通过____ 的方式增大摩擦.
“你入学的新书包有人给你拿,你雨中的花折伞有人给你打,你爱吃的那三鲜馅有人给你包,你委屈的泪花有人给你擦……”与这种情感相同的( )
⑴When do you eat breakfast?____ A.It's warm and sunny.
⑵Can you make a snowman now?____ B.No,it isn't.
⑶What's the weather like today?____ C.I eat breakfast at 7: 15.
⑷What would you like to do?____ D.No,I can't.
⑸Is it windy and cold?____ E.I would like to go swimming.
下列叙述中,正确的是( )
单项式-xy3的次数是( )