She knows that as a secretary she must be pleasant and helpful no matter how busy she is or what kind of ____ she may be in.
Many people think it very difficult _______ English.
The teacher asked the students __________ her _______ the word again.
Remember ______ the book here tomorrow.
---Let's have a rest, shall we? --- Not now. I don't want to stop _______ the letter yet.
---This physics problem is too difficult. Can you show me __________, Wang Lin? --- Sure.