When I took his temperature, it was two degrees above________.
I ____ go to bed ____ the telephone rang.
You may ask the teacher for help ____ difficulty.
The train ____ at present speed until it reaches Beijing.
Before becoming a pilot, he spent quite a long time ____.
Yang Liwei’s journey into ____ space took him 600,000 kilometres in ____ orbit, around the earth 14 times, in just over 21 hours.