[10-20 18:18:21] 来源：http://www.67xuexi.com 初三英语教案 阅读：850次
— Why is Kate absent? 凯特为什么迟到了？
— Because she is ill. 因为她病了。
since的另外一种用法，是表示“自从……以来”。
Where have you been since I last saw you?
上次我和你见面以后，你到哪里去了？
It is a week since we arrived here.
我们到这里来已经有一个礼拜了。
（2）本句中cover的用法，意思是“用……遮盖；覆盖”。
Snow covered the ground.
雪覆盖了地面。
She cried and covered her face with her hands.
她哭了，用手蒙住了脸。
The desk was covered with dust.= Dust covered the desk.
书桌上布满了灰尘。
7． …, he encouraged everyone to take part in protecting our lakes, rivers, seas and oceans.
……，他鼓励每个人加入到保护我们的河流、湖泊和海洋的行动中来，take part in意为“参加（活动）”一般表示在活动中还承担一定的职责。
He always takes an active part in all kinds of activities in school.他总是积极参加学校的各种活动。
join也有参加的意思，但是该词主要强调参加某项组织。如：He joined the party when he was eighteen years old.他十八岁就入了党。