Điền từ thích hợp vào chỗ trống

[ between, in, into, of ]

1. More research.....the effects of television on children's behaviour is needed.
2. It's not clear why many schoolchildren are reluctant to participate....sports
3. The contrast....facilities at top universities and those with lower status is considerable
4. An analysis.... attendance figures for primary schools suggests that absence eates are increaing amongst 5 to 7 year-olds