【单选题】To tell you the truth, I became a college student at 15. _____. [ ]
【单选题】通常离心喷雾干燥过程中物料与介质接触方式只有( )。
【单选题】If you want to change for a double room, you'll have to pay ______ $15.
【单选题】In an emergency, you should remain _____.
【单选题】--- Who are the teenagers gathering at the school gate? --- Well, if you _____ know, they are al
A.
15. --- Who are the teenagers gathering at the school gate? --- Well, if you _____ know, they are all my visiting students. A.need