据意填词&根据所给词适当形式填空
1.Dogs can help us () (find) () (lose) people.
2.He stops at the ()(cross) because of the red light.
3.Is it () to cross the road now? Yes , there’s the grern man.You can cross the road().You are in () when the green light on.(safe)
4.People have ()(keep) dogs for () (million ) of years.