—It’s going to rain outside. Don’t forget to bring a/an______!— OK! Mum!
—It’s smoggy these days. That’s terrible!—Yes, I hope to plant trees. ______ trees, ______air pollution.
School students ________ smoke because it is against the school rules.
_____ great fun it is to make a snowman in winter.
The flight to London was because of the heavy snow.
Tom is weak in physics. He always feels _______ before he takes a physics test.