电焊条由（）组成。
A.焊芯和药皮
B.铁条和焊芯
C.铜条和药皮
参考答案：A
去菀陈莝
If we learn to accept change and appreciate what is new and different, we will be well-prepared for whatever the future may have _______.
A．in vain
B．in store
C．in demand
D．in general
