Fill each blank with a suitable preposition to complete the sentences below.
1. by
=> by oneself = alone: 1 mình
2. In - with
=> in comparison with: nếu so sánh với
3. at
=> at college: ở trường đại học
4. across - at
=> come across: tình cờ gặp (former friend: bạn cũ)
=> at work: ở chỗ làm