当感知过的事物重新出现在眼前时,能够识别出来,这是
A.回忆
B.识记
C.遗忘
D.再认
E.保持
参考答案:D
根据要求改变下列句子,每空格填一词。
1. The boy jumps high.(改成感叹句)
______ ______ the boy jumps!
2. -Does Mike usually like making clothes?(作否定回答)
-No, ______ ______.
3. I have seven lessons every day.(用he或she改写句子)
______ ______ seven lessons every day.
4. It's seven twenty now.(对画线部分提问)
______ ______ is it now?
5. We have Chinese,Maths and PE on Monday morning.(对画线部分提问)
What _____ do you ______ on Monday morning?
A、B两列简谐横波均沿x轴正向传播,某时刻他们的波形分别如图甲、丙所示,经过时间t(t小于A波的周期),他们的波形分别变为图乙、丁所示,则A、B两列波的波速vA、vB之比可能是( )
A.2:1
B.1:2
C.1:3
D.3:1