一、
date back to 英?[de?t] 追溯到…… 常见用法： 1．
动词+～
?美?[de?t]
advance the date?提前日期 bear the date?注明日期 break the date?不遵守约定 bring forward the date?提前日期
2． 形容词+～
closing date?截止日期 early date?早期 fixed date?固定的日期 future date?将来的日期
3. 介词+～
from that date?从那时起 on a certain date?在某一日期 out of date?过时的 to date?到目前为止
例句：
All the objects are from the same excavation site in Sanxingdui and can be dated back to between 3,000 and 5,000 years ago.
所有的物品都来自于三星堆的一个挖掘点，时间可以追溯到3000到5000年前。
date back to＝date from
因追溯是从现在算起指向过去，所以这个短语常用一般现在时。 This custom dates back to the 16th century. 这风俗起源于16世纪。
This is an old building dating back to/dating from the 16th century. 这是一栋追溯至16世纪的古老建筑物。
练习：
1.英译汉My interest in stamp collecting dates back to/from my schooldays.
day a number of tourists take pictures in front of the tower，which ________ as early as 800 years ago.
A．dates back to B．is dated back C．dates back from D．was dated from
答案：
1.我从学生时代就开始爱好集邮。
2.选A。短语date back to 相当于date from，意为“追溯到，始于”。两者通常与过去的时间状语连用，但多用于一般现在时，且一般不用于被动语态。句意：每天都有许多游客在这座可追溯到800年前的塔前拍照。
二、 assume
英?[?'sju?m] ?美?[?'su?m] v．
假定；设想；假装；承担
常见用法： 1． 用作动词 (v.) ～+名词
assume a leading position?担任领导职务 assume a look of surprise?装出吃惊的样子 assume the right?夺取权力
2． ～+副词
assume baselessly?毫无根据地认为 assume falsely?错误地认为
assume groundlessly?毫无根据地认为 assume hastily?匆忙地认为
3． assume that 认为 例句：
So we think it is reasonable to assume they lived in these caves，regardless of the cold.
因此我们有理由认为他们不顾严寒，就住在这些洞穴里。 (牛津P104)It is reasonable to assume that the economy will continue to improve.
认为经济继续好转是有道理的。
(牛津P104)Let us assume for a moment that the plan succeeds. 咱们暂时假设计划成功。
(牛津P104)It is generally assumed that stress is caused by too much work. 普遍认为，紧张是工作过重所致。
Assuming that the proposal is accepted，when are we going to get the money
假定这个建议被采纳，我们什么时候能拿到钱
练习： 1.英译汉
A lot of people make the assumption that poverty only exists in the Third World.
all can go out for a picnic this afternoon－________that the others agree.
人教版高中英语选修八unit5 词汇讲解
