流行性腮腺炎患儿应采取呼吸道隔离至()。
A.体温正常
B.腮腺肿大完全消退
C.疼痛消失
D.头痛消失
E.血清或脑脊液中特异性IgM抗体恢复正常
参考答案:B
— I often play ___________ with Mike and play ___________ after supper. How about you?
— I play ___________.[ ]
A. chess; a yoyo; the violin
B. cards; with a yo-yo; the basketball
C. chess; with a yo-yo; the piano
D. cards; a yo-yo; the football
如图所示,质量为m的物体沿质量为M的斜面匀速下滑,M不动,则( )
A.M对地面的压力大小为(M+m)g
B.m对M的作用力的合力为零
C.地面对M的静摩擦力不为零,方向水平向左
D.m和M之间的动摩擦因数μ=tanθ