—It's said that an airport _______ in Yangzhou.

—It's true.That's what we are getting excited about these days. [ ]

A. builds

B. will build

C. is building

D. will be built

变电所所址的选择标高宜在( )年一遇的水位之上，否则所区应有可靠的防洪措施或与地区(工业企业)的防洪标准相一致，但仍应高于内涝水位。

A．10

B．20

C．30

D．50