鸡兔同笼,鸡a只,兔b只,则共有脚( )只.
2a+4b
Have you checked all the CDs _____ to the mountainous area next week?
A.sent
B.to be sent
C.sending
D.being sent
鳖甲除具有滋阴潜阳的功效外,还能()
A.软坚散结
B.补肾助阳
C.养阴清肺
D.凉血止血
E.燥湿健脾