[填句补文]He has also included symbols to show which ions are nutrients， and which are common in soil or water. ________.
A、There have been many attempts to redesign the periodic table since Dmitri Mendeleev drew it up in 1871.
B、And the size of element‘s symbol reflects how much of it is found in the Earth’s crust.
C、Railsback has still ordered the elements according to the number of protons they have.
D、Raisback has listed some elements more than once.
正确答案：B
答案解析：空格前的这句话是围绕symbol符号来讲述的;选项B也是符号，即：元素符号的大小反映出它在地壳中被发现的量。
[填句补文]When do people decide whether or not they want to become friends? During their first four minutes together， according to a book by Dr. Leonard Zunin. In his book， “Contact： The first four minutes，” he offers this advice to anyone interested in starting new friendships： ________. A lot of people‘s whole lives would change if they did just that.
A、That is not the time to complain about one‘s health or to mention faults one finds in other people.
B、Every time you meet someone in a social situation， give him your undivided attention for four minutes.
C、It is not the time to tell the whole truth about one‘s opinions and impressions.
D、He is eager to make friends with everyone.
正确答案：B
答案解析：空格前后句中出现了代词的呼应……this advice……that， 结合空格后句意(如果他们那样做的话，很多人的整个生活都会发生改变)判断that指代的内容是前句中提到的“这条建议”，所以判断空格处出现表意为“建议”的句子可能性最大，结合被选项的内容和用词判断B是答案。
[填句补文]The typical person living alone is neither old nor lonely. ________. The majority of these people have chosen to live alone. They are responding to decreasing social pressure to get married and have a family.
A、This is a dramatic change from the extended families of just a couple of generations ago.
B、The growing number of women with good jobs has done much to increase the number of people living alone.
C、There‘s more pressure to get married nowadays.
D、In fact， a quarter of the 23 million single people in the U.S. are under the age of 35.
正确答案：D
答案解析：空格后句中出现代词“these people”，而空格前句出现的人是单数形式，因此判断空格处应该出现表意复数的人，从而与these people相呼应。而且空格前句提到了“年龄(old)”，所以判断D是答案，a quarter of the 23 million single people是复数名词，而且D中提到了年龄(35岁以下)。
[填句补文]Bees are flying insects closely related to wasps and ants， and are known for their role in pollination (授粉)and for producing honey and beeswax.
________ The best-known bee species is the European honey bee， which， as its name suggests， produces honey， as do a few other types of bee.
A、There is only one queen in a hive.
B、Every bee does a job without being told.
C、There are nearly 20，000 known species of bees.
D、Bees do not like ice and snow.
正确答案：C
答案解析：答案选C。空格是首句，通过空格后的内容判断首句内容，紧着空格的那句话提到了关键词species，有关蜜蜂的种类的，然后浏览各选项，不难看出C选项最符合上下文语境。
【填句补文】He has also included symbols to show which ions are nutrients, and which are common in soil or water. ________.
A、There have been many attempts to redesign the periodic table since Dmitri Mendeleev drew it up in 1871.
B、And the size of element’s symbol reflects how much of it is found in the Earth’s crust.
C、Railsback has still ordered the elements according to the number of protons they have.
D、Raisback has listed some elements more than once.
正确答案：B
答案解析： 空格前的这句话是围绕symbol符号来讲述的;选项B也是符号，即：元素符号的大小反映出它在地壳中被发现的量。
