眼内屈光手术根据手术时是否保留晶状体分为两类:________和________,其效果的区别在于________。
参考答案:摘除晶状体;不摘除晶状体;是否维持原有的调节功能
the red switch on the left and the flying machine will swiftly go up into the air and its journey.
A.Press, begins
B.Press, begin
C.Pressed, begins
D.To press, to begin
钢材所含化学成分中,需严格控制含量的有害元素为()
A.碳、锰
B.钒、锰
C.硫、氮、氧
D.铁、硅