A:动脉血管收缩、心跳速率增加
B:动脉血管舒张、心跳速率减少
C:动脉血管舒张、心跳速率增加
D:动脉血管舒张、心跳速率维持不变
Many young people, most of ____were well-educated, headed for remote regions to chase their dream.
请简要说出检验物体是否带电的三种方法?
已知函数f(x)=cos(2x+ϕ)满足f(x)≤f(1)对x∈R恒成立,则( )