—Where is kate?
—She _____ in her room. [ ]
A. read
B. reads
C. is read
D. is reading
答案:D
M={x|x-a=0},N={x|ax-1=0},若M∩N=N,则实数a的值为 ______.
硝普钠降压的作用机制是()
A.阻止钙离子进入心肌细胞及血管平滑肌,使心肌收缩力降低
B.扩张静脉和选择行扩张动脉
C.直接扩张动脉和静脉
D.减慢心率,降低心排血量,抑制肾素释放
E.抑制血管紧张素与受体结合