It was in the lab______ was taken charge of by Professor Zhang ____ they did the experiment.
---You are so lucky. ---What do you mean ____that?
Let's walk over ___the shop on the other side of the street.
_____most students, she was always well prepared and never came to class late.
The doctor will be free ____.
The boy ought to have gone to school ___, but he slept ___noon.