___________ the man who lost the purse, Mike had to stay there longer.
Some steps have been taken to protect the forest _______.
She can’t get down to work because she was deeply _______ by the news of his death.
--- Are you going to attend Jay Chou Concert in Suqian this weekend?--- ______. It’s too good a chance to miss. I’m his die-hard fan.
--- Who ______ it be that is singing in the next room?--- It _______ be Lucy, but I am not sure.
Not until World War II ______ to use new chemical techniques to purify penicillin.