Not until my mother told me the sad news last night I knew that our neighbor was killed in a car accident the week before.()

单项选择题Ever since the world began nations have difficulty in keeping peace with their neighbors.()

A. Ever since
B. began
C. have difficulty
D. keeping

单项选择题The old artist is in the habit of going for a walk in the park every morning except it rains.()

A. in the habit of
B. going for
C. morning
D. except it rains