运算器由很多部件组成，其核心部分是( )。
A．数据总线
B．算术逻辑单元
C．累加器
D．多路开关
参考答案：B
长拳的手法主要有拳、掌、勾（冲拳，劈拳，撩拳，贯拳，推掌，穿掌，亮掌，挑掌，顶肘，格肘），步法主要有马步、弓步、仆步、虚步、歇步。
—There are always many volunteers in great events, _______?
—Yes. Many hands make light work ! [ ]
A. aren't there
B. are there
C. aren't they
D. are they
