采用压力法保养时，停炉期间锅炉的水温不应低于（）
A.70℃
B.80℃
C.90℃
D.100℃
参考答案：D
He was really _____to find that John’s joke was so______.
A．surprising; amused.
B．surprised; amusing
C．surprising; amusing
D．surprised; amused
设PC机中单字节带符号的整数；A=01001110，B=10100001，则A-B的结果是______。
A．11101111
B．10010001
C．10101101
D．00101101
