下列关于声现象的说法正确的是（ ） A．小提琴演凑者通过手指在弦上按压位置的变化

I play ___________ piano on Sundays.[ ]

A. a

B. an

C. the

用所给词的适当形式填空。

1. Kate ________ (be) ill yesterday.

2.The students had a ________ (terribly)  school trip.

3. It rained all day. And I ________ (stay) at home.

4. Did you go ________ (boat) on the lake yesterday?

5. —What are you doing?

    —I ________ (look) for my pen.

6. Jenny _______ (read) a lot of books last year.

7. He _______ (watch) a video about sharks yesterday.

8. Joe ________ (put) on his coat and went out.

下列关于黄埔军校的叙述，正确的有

①1924年6月在广州创办的②它的名称是陆军军官学校③周恩来任校长④军校培养了大批军事人才[ ]

A．①②④

B．①②③

C．②③④

D．①②③④

市场细分化是由谁于20世纪50年代提出的营销概念（）

A.温德尔•史密斯

B.马斯洛

C.霍夫施塔德

D.蒙代尔

道德态度的养成是道德品质形成的重要标志。