---Have you ever been here before?---No. this is the first time that I to the Great Wall. A comes B have been C came D had been
Harry is feeling uncomfortable. He _____ too much at the party last night.
It remains to be seen _______the newly formed committee’s policy can be put into practice.
— How far can you run without stopping? — ________. I’ve never tried.
Anyone, once _______ positive for H7N9 flu virus, will receive free medical treatment from our government.
My uncle hasn’t been able to quit smoking, but at least he has_________ .