it is dangerous for children to swim alone.为什么用 alone?动词后不应该

it is dangerous for children to swim alone.为什么用 alone?动词后不应该 it's,swim,dangerous,to,alone(.) 连词成句 it's,swim,dangerous,to,alone 连词成句 It is dangerous for little children to swim in the river.为什么 It's d__ for the children to swim alone in the river.They bo It's d___ for the children to swim alone in the river. in,is,swim,children,to,river,the,dangerous,it,really,for It may be dangerous to swim in the pool alone.改为同义句 Don't swim in the l___ alone.It's dangerous. It is ()dangerous for children to climb a mountain to,out,it's,dangerous,late,alone,stay(.) to,out,it's,dangerous,late,alone,stay