氮的氢化物NH3、N2H4等在工农业生产、航空航天等领域有广泛应用.
在光滑斜面上的物体实际受到的力有 ( )
-- Mum, may I watch TV for a while?
-- Of course, if your work .
Mr. Smith, together with his wife and children, ____ (be) going to visit Beijing next year.