—_________is very interesting to swim in the river in summer,but it’s dangerous.
I swam in the river and caught a small fish yesterday afternoon.----_____
---how many students are there in the classroom? ---_____Idon’t know where they have gone.
Our playground is not so tidy and beautiful as before. Students must _____ dirty things on it.
I _____ this book for two weeks. I have to return it now.
—Do you think a radio is useful in learning English? —Sure. A radio can _____ listening English songs and reports.