___________ in hard seats for 6 hours, we finally stepped out of the train tiredly.
Can _____ be in the desk _____ you have put my letter?
Time should be made good use of ____ our lessons well.
---What do you think made the woman so upset? --- _____ weight.
The research is so designed that once ____ nothing can be done to change it.
______ in thought, he almost ran into the car in front of him.