平面简单静定桁架的内力计算方法有两种：（）
A.节点法
B.截面法
C.位移法
D.力法
E.应变法
参考答案：A, B
----what do you think of the Chinese language today?
----Quite popular. It______ in communicating with other countries. More and more foreign friends are learning Chinese.
A．plays an important role
B．is playing an important role
C．has played an important role
D．is being played an important role
当使用硬膜外麻醉时，能加速局麻药起效和延长作用持续时间，并提供最大的感觉和运动阻滞深度的做法是
A．1：200000加入肾上腺素B．增加局麻药的容量C．增加局麻药的浓度D．增加局麻药的剂量
