8B Unit21.I've been there be fore. 我此前去过那里。①before 副词“此前”。常与目前完毕时连用，也可与一般过去时连用。He has never seen such a huge stone before.他此前从未见过这样大的石头。②before 介词或连词“在……之前”，可表达时间、位置、次序等。My father usually goes to bed before 9:00 p.m.我父亲一般在晚上 9 点之前睡觉。（介词）Turn off the light before you leave the room.离开房间前关上灯。（连词）3.Can I join you?我可以和你一起去吗?①join 及物动词“加入”，表达加入某一组织、党派、社会团体或某一人群中，从而成为其组员。join 后常出现 club，army，team，group 以及表达人称代词宾格的单词等。My father joined the army after he finished middle school.我父亲中学毕业后就参军了。Will you come and join us for supper? 你乐意来和我们共进晚餐吗?②take part in“参与/参与某项工作、活动、游戏或会议等”，强调参与者有积极的态度，并起到一定的作用。take part in 之后接名词或动名词。=join in。Would you like to take part in/join in the English party? 你乐意参与英语晚会吗？Everyone can take part in gardening. 每个人都可以加入到园艺活动中来。③join sb.in...“参与到……中”。A lot of students are playing football on the playground. Let’s join them in playing football! 许多学生正在操场上踢足球，咱们加入到他们当中吧！4.excited 形容词为“感到兴奋的，感到激动的”。be excited at/about sth 对某事感到激动；be excited to do sth.激动地去做某事；be excited that+从句。She was really excited about going to Beijing. 她对北京之行感到非常兴奋。I was excited that I could have the chance to study abroad.我很激动，我能有机会出国学习了。We’re very excited about the exciting news.我们对这个激感人心的消息感到很激动。5.I don't think it'll be a holiday for me.我认为对我来说这将不是一种假期。这是一种具有宾语从句的主从复合句，I don't think 是主句，it'll be a holiday for me 是宾语从句。当主句主语为第一人称，think,believe 等动词后的宾语从句为否认句时，要将否认词转...
