7. Раскройте скобки, употребляя требующуюся форму инфинитива.1. They seemed (to quarrel):

7. Раскройте скобки, употребляя требующуюся форму инфинитива.
1. They seemed (to quarrel): I could hear angry voices from behind the door.
2. They are supposed (to work) at the problem for the last two months.
3. The only sound (to hear) was the snoring of grandfather in the bedroom.