If the customer requests a carrier other than truck, he must bear the additional charge.
如果顾客坚持用卡车以外的运输工具,就必须负担额外费用。
It is the natural frequency of emission of the hydrogen atoms in space and was discovered by us in 1951;
这个频率是空间氢原子释放的自然频率,是在1951年被人类发现的。