Complete the sentences with the correct grammar form

1. I think there
   [aren't|won't] be traffic jams in the nearest future.
2. When I
   [will come|come] home, my parents will meet me.
3. She will join us tonight if she
   [has|will have] free time.
4. Helen
   [calls|will call] you when she returns back home from the gym.
5. He believes that the Earth
   [is|will be] even more polluted and overpopulated in future.