针对变动幅度较大,周期大约在10秒至2-3分钟之间,属于冲击性的负荷变动进行的频率调整称为()
A、一次频率调整
B、二次频率调整
C、三次频率调整
参考答案:B
按要求完成下列句子。
1. He wrote a letter to his dad in New York. (改为现在进行时)
Now he ____________ ____________ a letter to his dad in New York.
2. It's a quarter to ten. It's time for cartoons. (改为近义句)
It's nine ____________. It's time ____________ ____________ cartoons.
3. He does some exercise every morning. (改一般疑问句)
____________ he ____________ exercise every morning?
4. She saw the film last year. (对画线部分提问)
____________ ____________ she ____________ the film?
5. The station is about 6 kilometers away from our school. (对画线部分提问)
____________ ____________ is the station from your school?
6. She is going to buy a new hat, because her hat is too old. (对画线部分提问)
____________ ____________ she going to ____________ a new hat?
鼻黏膜功能生理调节中,下述哪一项是正确的()。
A.交感神经兴奋时,鼻黏膜血管收缩,腺体分泌增多
B.交感神经兴奋时,鼻黏膜血管扩张,腺体分泌减少
C.交感神经兴奋时,鼻黏膜血管收缩,腺体分泌减少
D.交感神经兴奋时,鼻黏膜血管扩张,腺体分泌增多
E.副交感神经兴奋时,鼻黏膜血管收缩,腺体分泌减少