The Australian boy has a good __________ of Chinese and can express himself freely in it.
When we climbed up to the top of the mountain, we were all ___________.
I ________ while reading the English textbook. Luckily, my roommate woke me up in time!
Every year, the coal workers their lungs X-rayed to ensure their health.
We ________ to go skiing tomorrow,but there’s no snow,so we’ll just stay home instead。
—Has Sam finished his homework today?—I have no idea. He ________ it this morning.