画出下列用电器的电路元件符号.
(1)灯泡:______; (2)电动机:______.
(1)灯泡的符号:
(2)电动机的符号:
故答案为 (1)
;(2)
.
—When I speak English, I always make _____ .
—Don't be afraid of that. That's how we learn.[ ]
A. trouble
B. mistakes
C. influence
D. challenges
低压活塞式压力计应用变压器油,高压则用蓖麻油。