The song ______My heart will go on is li

---Stanly has graduated from the university.

---It’s no wonder that I can’t see him these days. He ___ in the city for six years.

A．has stayed

B．had stayed

C．stayed

D． has been staying

技术方案经济效果评价的基本内容，包括（）。

A.盈利能力

B.偿债能力

C.财务生存能力

D.可行性能力

E.设备利用能力

信石的主要成分是

A．硫化汞

B．二硫化二砷

C．二硫化铁

D．三氧化二铁

E．三氧化二砷

It takes me half              hour to do my homework every day. [ ]

A. a

B. an

C. the

D. /

管径为250mm的生产废水、雨水管道敷设的最小坡度应为0.0035。( )