密封源按活度不确定性可以分为()
A.检查源
B.参考源
C.中子源
D.标准源
参考答案:A, B, D
Every year in the U. S. , colleges and graduate schools continue to highly () trained people to compete for jobs that are not there. As a result, graduates cannot enter the professions for which they were trained.
A. turn out
B. work out
C. make out
D. bring out
要使羹的汤质柔滑,掌握烩制时调芡的时机非常关键,最好是在()。