I don’t know if my uncle_______. If he______, I will be very happy.
What did you buy during your last vacation? I __________ a hat.
--- ___________ there any sharks in the aquarium? --- No, we didn’t see any.
It’s not good for people __________ waste water (污水) into the river.
Every student in Miss Chen’s takes turns __________ the classroom every day.
Please tell your partner _____________ make your favorite smoothie.