--- Do you know what Tom does all day ?

---- I know he spends at least as much time watching TV as he ____________his lessons.

A．is doing

B．does

C．spends to do

D．does doing

两字代码含有数字的航空公司是（）。

A.深圳航空有限责任公司

B.海航集团有限公司

C.四川航空股份有限公司

D.上海航空股份有限公司