设a、b∈{1,2,3},则方程ax+by=0所能表示的不同直线的条数是____ .
如图为丙氨酸分子结构模型,下列关于丙氨酸说法不正确的是( )
He donated his money to poor people, so we realized that he had a heart __________ love.
澳门回归祖国后,社会平稳,经济继续发展,下列关于澳门的说法,正确的是( )