However, at times this balance in nature is ______, resulting in a number of unforeseen effects.

People were not allowed to enter the reading room because it _______

n my room once a week, and the job_____ me two hours

_ How was your holiday lastweekend _Wonderful.I_______to the Great Wall with my parents.

Mr Li began to teach in this school, _______, some time later, she became popular with the teachers and students for her excellent teaching levels.