要在4点40-4点50之间回家中包不包括40和50?

时针旋转了（ 12.5度）,分针旋转了（150度 ）；
4点40分时,时针和分针的夹角的度数为（100度）



分针转了（40-15）/60x360=150°



时针转了150x1/12=12.5°


4点40分时,时针与分针的夹角是
40/60x360x（1-1/12）-4/12x360=100°

The number of new books in the library is too small.
The books on the shelt aren't tiny.
a light in the reading room

nine past eight,a quarter past twelve,twenty to five,five to three