用户程序与操作系统之间通过______接口进行通信。
参考答案：程序
The old man didn’t feel though he stayed on the hill ．
A．alone；lonely
B．alone；alone
C．lonely；alone
D．lonely；lonely
情景对话.
A: 1. ______! I'm John.
B: Hello, John, I'm Tom. 2. ______ to meet you.
A: Nice to 3. ______you. too.
