Most people are familiar with the idea that all matter in the universe ________ atoms.
This is the second time that I_______ London. The first time I_______ here was on Christmas Day last year.
--- How do you find Mr Li’s lecture?--- Good indeed. It_______ many problems we have come across in our study.
_____it is to jump into a river to swim on such a hot day.
________ the final exam________ up soon, we should get down to our studies.
In recent years, with the help of our teacher, I have made_____ rapid progress in ____math.