We were busy ________ (get) things ready for the trial production when he phoned us.
Some molecules are large enough ________ (see) under the electronic microscope.
I shall never forget ________ (meet) the late Premier Zhou during his inspection of our factory.
某队请求暂仃和换人时,应向那个裁判员提出()
A. 第一裁判
B. 第二裁判
C. 记录台