氢分析仪测氢浓度为PPm级时,相对偏差≤±()%
A、2
B、5
C、8
D、10
参考答案:B
---Imagination important in science, and it helps us dream up our future.
---You are definitely right. If only something allow me to see insects and spiders magnified without getting close to them.
A.was; would
B.is; will
C.will be; can
D.is ;could