一位同学水平向右推放在水平地面上的桌子没有推动,则下列说法中正确的是( )
Believe it or not, no bread eaten by us is so sweet as________earned by our own labour.
Last year the teacher told us that the Earth ____ (go) around the Sun.
下列动物行为中,属先天性行为的是 ( )