Решение:
Заполним пропуски глаголами в Present Continuous:
- Look! Chuckles is climbing the tree.
- Lulu is making a sandcastle at the moment.
- Larry and his friends are playing basketball now.
- I am reading a very interesting book.
Ответ: 1. is climbing, 2. is making, 3. are playing, 4. am reading.