在突触传递过程中，促使突触小泡中递质释放到突触间隙中的离子为（）
A.Ca2+
B.K+
C.Na+
D.Cl-
E.Mg2+
参考答案：A
Henry won't deal with his problems ______ he can regard them as challenges. [ ]
A. after
B. unless
C. but
D. even though
“电台设备”的业余无线电通信常用缩语？
