—The classroom is ____ clean ____ it was yesterday.— Sorry, I forget to clean it.
—When will the train ______ here? —In five minutes.
I usually ______ sunglasses outside in the sun.
The poor girl needs an operation. But it will ________ a lot of money.
It’s impolite __________others. Always wait politely.
---How can we help _________ people? --- We can help them cross the road.