扫描二维码，直接登录
题库 / GMATLA-SC-84
In 1981 children in the United States spent an average of slightly less than two and a half hours a week doing household chores; by 1997 they had spent nearly six hours a week.
chores; by 1997 they had spent nearly six hours a week.
chores; by 1997 that figure had grown to nearly six hours a week.
chores, whereas nearly six hours a week were spent in 1997.
chores, compared with a figure of nearly six hours a week in 1997.
chores, that figure growing to nearly six hours a week in 1997.
题目分析：
本题的关键，在于对实物代词they的理解。
选项分析：
选项A：本选项在语法上没有问题。但是仔细观察在划线部分出现了代词they，其指代对象为出现过的名词children。本选项按照字面意思翻译为：
在1981年，美国的小孩平均每周花两个半小时去做家务劳动，但是在1997年，他们会花6个小时做家务劳动。
由于they是实物指代，也就是指代前面出现过的那个名词，所以译文中的“他们”指的在1981年出现过的那些小孩。这是不正确的，假如在1981年，小孩们是5岁，那么到了1997年，这些小孩变成了21岁，即，they指代这些21岁的“小孩”。显然地，本题想比较的是两个年份小孩的情况，而不是同一群小孩在两个年份的区别。当然，也可以改为：
by 1997 children had spent nearly six hours a week.
选项B：Correct. 本选项在语法和逻辑上均是正确的。
选项C：whereas身后是被动句，其缺少真正的执行者。单纯读划线部分，我们只能知道有将近六个小时被花费了，至于究竟是谁花费了这六个小时，我们不得而知，自然本选项就无法和In 1981 children in the United States spent an average of slightly less than two and a half hours a week doing household chores形成对比（whereas）关系。
选项D：compared with a figure of nearly six hours a week in 1997是一个过去分词短语，它只能就近修饰身前的household chores。在逻辑上，和数据比的，不能是家务劳动。
选项E：本选项是独立主格结构。依据图形背景原则，若本选项正确，则grow这个动作必然在时间上长于主句的spend动作。但在本题中，两个动作处于两个年份，无法判定谁持续的时间长于谁，因此，只能用分号两个独立的句子。
they指代的是原来那批孩子，但是其实主体已经不是那批孩子了，是另外一批了，所以they错误。
A：Since "spend nearly six hours a week", like ""perform well", doesn't represent a fundamental change of state or indicate a difference along the timeframe, thus the combination of "had spent nearly six hours a week" and "by 1997" makes no sense here.
whereas身后是被动句，其缺少真正的执行者。单纯读划线部分，我们只能知道有将近六个小时被花费了，至于究竟是谁花费了这六个小时，我们不得而知，自然本选项就无法和In 1981 children in the United States spent an average of slightly less than two and a half hours a week doing household chores形成对比（whereas）关系。
C选项whereas后面没有spend的主语，不构成和前句的逻辑关系。
C选项whereas后面没有spend的主语，不构成和前句的逻辑关系。
B虽然也没有说明是谁，但that figure就代表了和前句一样的spent by children in the US
that figure growing to nearly six hours a week in 1997指figure在1997这一年长到6小时，没有体现出增长过程
B，grown to 6是一种成果，用by+时间是可以的；that figure概括了或者说指代之前提到的2个半小时，ok
C，将主动式转变为被动式不带by sb，去除了逻辑主语，但这里应该要说明是children spent而不是别的人spent 6 hours才能满足语意。
D，要么写the figure要么直接写出来数字是多少，不能用the figure of 4000，冗余。如：In 1990 the population of Las Vegas was 400,000, but by 2010 that figure had grown to 1,200,000.这里用that figure，因为不能写成400000 had grown to 1200000.
如果不涉及触达某种成果或发生状态的改变，不用by，如：The scholarship was offered to graduate students who had graduated from their undergraduate institutions between 2000 and 2005.
A，by 1997 they had spent nearly six hours a week.spend是一个持续的状态，在本题的前后语境里，既没有发生改变也没用持续以至触达一个结果，不能用by+时间；B，by 1997 that figure had grown to nearly six hours a week.grown to表示触达一个结果，意思是在1997年的时候或之前的任何一个时间点，这个数字增长到了6小时。
by+时间修饰发生改变的状态或维持动作以至触达某个成果，如：
Anyone who had not performed well enough to qualify for the Olympic Trials by December could no longer try out for the team.意思是anyone指代的人在1990年前没有达标，如果直到1990年还没有完成从不达标到达标这一转变的，会失去留队资格。
Pomeranians who have attained a body weight of fourteen pounds by the age of 1 year are classified as "throwback Pomeranians".意思是只要在1岁前的任何一个时点触达14磅这个状态，就可以被分级为"throwback Pomeranians".
whereas nearly six hours a week were spent in 1997.没有说s是谁spent，那么也可以是比如大人工作花费6小时，与前句没有了逻辑关系。
不要管时态
有明显的时间点的话，had就一般不冲突；that figure growing变成了附属的独立主格，而应该是并列的关系。
PREP07 Test 2-96 ： There are hopeful signs that we are shifting away from our heavy reliance on fossil fuels: more than ten times as much energy is generated through wind power now as was the case in 1990. 举一反三
PREP07 Test 2-96 ： There are hopeful signs that we are shifting away from our heavy reliance on fossil fuels: more than ten times as much energy is generated through wind power now as was the case in 1990. 举一反三
B用过去完成时是可以的，因为用了；－－分号。ｂｙ 1997就提供了一个过去的时间点，而达到6小时一周是发生在1997年之前的。C继续错~~~~D 中compare with就近修饰家务活，就不对了。
C中whereas前后两句话没有共同描述的对象，所以两句话之间缺乏了转折关系。E中独立主格结构，但前后两句话时间明显相差很远，不能用。
choice b is ok:
- past perfect makes sense, because the figure had finished growing by then. (note that the past perfect makes sense here, even though there isn't an explicit 'second event': in the present, we'd say the figure has grown to such-and-such a level, so, by 1997 [a past date], we'd say it had grown to such-and-such a level.
这题挺好的！
因为过去完成时，排除了AB。。。结果B是对的，想Ron的逻辑还是觉得有点不明白
choice c: needless use of the passive voice. at best this is awkward, and at worst it makes the reader think that the 6 hours of chores were being performed by someone else (i.e., not children).