关于叶轮式增氧机能达到的作用的论述,正确的是()
A.只能改善表层溶氧状况
B.只能改善底层溶氧状况
C.可以改善水体各层溶氧状况
D.以上都错误
参考答案:C
微启式安全阀泄放量小,一般只适用于盛装()的压力容器安全防护;开启式安全阀泄放量大,回座性能一般只适用于盛装()的压力容器安全防护。
We expect ____ large orders from Europe in the near future.
A. receive
B. to receive
C. to receiving
D. being received