Dear Jenny, thank you for your letter which ______ on April 1st.
We Chinese must stick to One-China policy, ____ is of great importance to China.
It was in the lab ______ was taken charge of by Professor Harris _______ they did the experiment.
This nice magazine _____ your brother.
The restaurant is _________my uncle.
Can you believe that in ____ a rich country there should be ___many people.