Which of the following is NOT true about drama according to the passage().

A.It was thought to begin in the Roman Empire.

B.It was thought to start the human interest in storytelling.

C.It might come from rhythmical and gymnastic dances.

D.It might come from imitations of animal movements and sounds.

防止锅炉中产生磷酸盐铁垢的主要方法有（）。

A.严格控制锅炉水PO3-4的含量

B.提高联氨浓度

C.减少给水的含铁量

D.提高PH值