Do you know where I can have my shirt ____?
A. shorten
B. shorting
C. Shortened
D. Shorts
Which of the following broadening belongs to the inhomogeneous broadening? ____?
A. collision broadening
B. natural broadening
C. intrinsic broadening
Doppler broadening
When was the first laser invented in the world?____
A. 1960 year
B. 1962 year
C. 1961 year
D. 1963 year
Which is not a property of lasers that differs from ordinary light sources? ____?
A. The divergence angle is relatively small
B. Laser power is very high
C. Lasereasily produces interference fringes
D. The laser can shine very far
微信支付 
支付宝支付