I find it difficult _______ up Mount Tai.
All the students know shouting at the elderly is impolite.
We can’t work out this problem. Can you tell us ______ ?
—Don't talk in the library. Always keep quiet here. —_________.
A number of foreign visitors _____ Chengdu many times because it is such a beautiful city.
There was interview with Yao Ming on CCTV-5 yesterday evening. But it was a pity that I missed beginning.