--The river used to be clean. How does it become dirty? -- There are many factories ________ waste water into it. A. pouring B. pour C. poured
Premier Li said we should speed up the Internet and lower the .
— Look! The old man ______ a big box into the house. — Let’s go and help him.
When you play sport, you need to guard ______ accidents.
Do you know ______? I want to see a funny film.
The Silk Road was ______ long that it passed through many countries.