长通滤光片
参考答案：
能使特定波长以上的光通过，特定波长以下的光不能通过的滤光片。
The school days are busy enough, yet the Taylors try hard to fit as much as possible their kids'
lives. [ ]
A. in
B. into
C. on
D. at
消防头盔的下颌带宽度大于（）mm。
A.10.0
B.12.0
C.15.0
D.18.0
