在一定压力下，纯氨的沸点（）此压力下氨水的沸点。
A.高于
B.等于
C.低于
D.无法确定
参考答案：C
His aunt’s letters ________ of those beautiful days when they used to live together
in his hometown.
A．call him on
B．call him for
C．call him up
D．call him in
剪纸题材广泛，包括（）等。
