单项选择题
One day while Mr. King was working, he had a/an（）：his left leg was badly injured.
A.business B.accident C.matter D.event
单项选择题 One cannot learn a foreign language well（）he studies hard.
单项选择题 One and a half hour（）since we arrive. No one has come to meet us.
单项选择题 On my left（）a wide river; on my right, a dark forest.
