用薄膜过滤法做细菌及霉菌的阳性菌计数时用做平行吗？
参考答案：
需要做平行试验（2张薄膜）。
These diagrams are especially helpful when we have a concrete problem ________ at hand.
A．be solved
B．to solve
C．solved
D．being solved
如何处理能源与环境的关系？
