公安消防部队战备等级分为哪几类？
参考答案：
经常性战备、二级战备、一级战备。
. The new English teacher as well as the excited students _____ a new English song on the Internet.
A．are learning
B．is learning
C．have learned
D．has been learned
经行头痛《张氏医通》有哪项记载（）
A.经行辄头痛
B.经行头痛
C.经行头胀痛
D.经行巅项痛
E.经行偏头痛
