系统工程是系统科学的基础理论。
参考答案：错
— I've never found a better job.
— _______![ ]
A. Life is hard
B. Don't worry
C. Congratulations
D. Sorry to hear that
波峰焊焊接中，较好的波峰是达到印制板厚度的（）为宜。
A.1/2～2/3
B.2倍
C.1倍
D.1/2以内
