A：直角
B：锐角
C：钝角
D：不能确定
Don't open the door. It's cold. Please ____ the door.
下列各组中，不属于同一性状之间的差异的是（ ）
Nowadays, more and more students choose to take a gap year. That is, they take a year ____ between the ending of high school and the beginning of university.
