We ____ (go) to the Science Museum last Sunday.
①煤油燃烧过程中,其热值大小____;
②燃气对火箭做功,燃气的内能会____(两空均选填“增大”、“减小”或“不变”).
曲线的极坐标方程ρ=4sinθ化成直角坐标方程为( )