Заполните правильный предлог:
1. Sam checked ________ the items on his shopping list as he went around the supermarket.
2. I returned the key to my room after I checked ________ the hotel.
3. My parents often come to my shool to check ________ how I'm doing.
4. I arrived at the hotel and checked ________ .
5. Tom checks _______ his son now and then to make sure he's studying hard.