（ ）是网络的心脏，它提供了网络最基本的核心功能，如网络文件系统、存储器的管理和调度等。

单项选择题A: Thank you for looking after the eat for me.B: (). I love cats.

A. Thank you
B. It’s my pleasure
C. By the way
D. No, of course not
E. Never mind

单项选择题A．This tour is the chance of lifetime．B．It goes all over North America and South America．C．It looks like you’re dreaming about something．D．You’ll have to quit school and your job at the store．E．My agent wants me to go on a tour with Art’s Jazz Band．F．Have you told anyone about this yetG．It would be a great opportunity!

单项选择题通常，计算机是计算机系统的简称，从系统的角度看，它应包括（ ）。

单项选择题A．This tour is the chance of lifetime．B．It goes all over North America and South America．C．It looks like you’re dreaming about something．D．You’ll have to quit school and your job at the store．E．My agent wants me to go on a tour with Art’s Jazz Band．F．Have you told anyone about this yetG．It would be a great opportunity!

单项选择题A. What a beautiful dress!B: (). I just got it yesterday.

A. Thank you
B. It’s my pleasure
C. By the way
D. No, of course not
E. Never mind