单项选择题液晶的电光效应是指因外电场引起的液晶( )改变A. 折射率B. 磁学性质C. 光学性质D. 介电常数
单项选择题Further steps are needed in the COP21 agreement to lock in the 2°C vision more strongly so that it anchors future expectations. A、secures B、achieves C、locks in
