Помогите пожалуйста. Нужно сделать два задания.

1. The  babies were looked after by the young mothers with great care. 
2. The roof of the house will be painted by boys.
3. In summer, the horses are often driven by the boys to the fields.
4. A number of important experiments have been made by them in this laboratory.
5. At twelve o'clock, the trucks were being loaded by the workers.

1. at.  2. for.  3. to.  4. for.