x﹣（2x﹣y）的运算结果是[ ]
A．﹣x+y
B．﹣x﹣y
C．x﹣y
D．3x﹣y
答案：A
如何更换气门座圈？
How do I get to Cairo?（）
A.I‘m sorry. I can‘t understand.
B.You could catch the 9:30 flight and change at Paris.
C.I‘m afraid you have missed the flight.
D.I‘m glad to show you the way
