——Are your books on _________ chair?
——Yes, they are.
A:an
B:a
C:the
D:/
If you want a____(永久的)job,you will have to be devoted to improving your skills.
一种药品原价每盒25元,经过两次降价后每盒16元.设两次降价的百分率都为x,则x满足( )