The PRC on October 1st, 1949. [ ]
A. was found
B. founded
C. was founded
D. was finded
答案:C
和激光器相比,发光二极管工作特点是什么?
校配好无框眼镜后,还应使顾客注意,摘戴眼镜时要(),避免镜片破裂。
A、单手摘戴
B、双手摘戴
C、凭个人习惯
D、以右手为主