（1） Students can’t leave the class early without the teacherˈs ________（许可）.
（2）Vancouver is Canada’ s most beautiful city, s_________ by mountains and the Pacific Ocean.
（3）_________(凝视，盯着看) at people is considered rude in Britain and young children will be scolded by their parents if they look too long at another person.
（4）Eating carrots b________ your eyesight.
（5） I cannot solve the problem on my own, so I must ________ (咨询) my teacher.
（6）You did wrong to your little sister, so you should a________ to her for your fault.
（7）The custom of arranged marriages still _________（存在）in many countries.
（8）Evidence gained from observation and experiment is often used to _______(证实)a scientific theory.
（9）I’m taking a course on political _________(理论).
（10）Smoking is extremely h_________ to your health.