Stephen lives in a ___________ flat with a big balcony. And he often chats with his friends _________ the balcony.

How was the professor’s lecture?—Impressive. Thank you so much for giving me a lift during the rush hours. If not, I ________ the lecture today.

The world today _____ different without the amazing discoveries produced by great scientists.

Hard work and lack of sleep has ______ herbeauty and youth in recent years．

He is not ________to do his homework., which makes hisparent worried