下面物理量()不是交流电的三要素之一。
A.幅值
B.频率
C.初相
D.相位差
参考答案:D
用gather或collect的适当形式填空。
1. Mary went along the path _____ wild flowers.
2. He has been _____ stamps for 10 years.
3. The peasants are busy____ crops in the fields.
4. They will _____ at 8:00 at the park gate.
脾的阴阳属性是阴中之至阴。