为了减少锅炉内水渣的危害，可以采取（）的办法除去炉水内水渣。
A.连续排污
B.定期排污
C.停炉放水
D.加磷酸盐
参考答案：A, B
Zhang Yining has trained continuously for six hours. ______ she is tired out.
A．There is no wonder
B．There is no need
C．It’s no wonder
D．It’s no doubt
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