方程（3x-4）2=3x-4的根是______．

设矩阵A=

，矩阵B满足ABA^*=2BA^*+E，其中A^*为A的伴随矩阵，E是单位矩阵，则|B|=______．

HACCP计划中，生产操作限值范围的设定应比关键控制限值更窄。

Valentine’s Day is named for Saint Valentine, an early Christmas churchman who helped young lovers. Valentine was killed for his Christian beliefs on February 14 more than 1700 years ago, but the day which is named after him is even earlier than that.

More than 2,000 years ago, the ancient Romans celebrated a holiday for lovers. As part of the celebration, girls wrote their names on pieces of paper and put them in a large container. Boys reached into the container and pulled one out. The girl whose name was written on the paper became his lover or sweet heart for a year.

Now, lovers still put their names on pieces of paper and they sent each other Valentine’s Day cards that tell of their love. Sometimes they also send gifts, like flowers or chocolate candies. Americans usually send these gifts and cards through the mail system. But some use another way to send this message. They have it printed in a newspaper. The cost is usually a few dollars. Some of the messages are simple and short, “Jane, I love you very much”. Others say more. This one, for example, “Dan, Roses are red. Violets are blue. I hope you love me as much as I love you. Forever, May.”

Most of the newspapers that print such messages are local, but USA Today is sold throughout the United States and 90 other countries. This means someone can send a Valentine message to the lover in a far-away place almost anywhere in the world. These messages cost 80 dollars and more. An employee of USA Today says readers can have a small heart or rose printed along with their messages this year. Will this kind of Valentine’s Day message reach the one you love? Well, just make sure he or she reads the newspaper.

小题1:When was the day named after Valentine?

A．More than 1700 years ago before Valentine’s death.

B．More than 2, 000 years ago.

C．On February 14.

D．It is not mentioned in the passage.小题2: Which of the following is Wrong about the ancient Romans holiday in the text?

A．Girls put paper with their names into a container.

B．Boys and girls became sweet hearts by chance.

C．Girls and boys chose life lovers in the holiday.

D．It was celebrated as a holiday for lovers.小题3:Now lovers celebrate Valentine’s Day _________.

A．like what the ancient Romans did

B．by sending gifts to each other

C．by printing newspapers

D．by spending lots of money小题4: What can we learn from the text?

A．The ancient Roman girls were more easy-going.

B．Valentine was killed for not helping the government.

C．USA Today helps readers to send roses with printed messages.

D．Valentine was honored for his Christian belief and warm heart.小题5:The text is written to _________.

A．tell us something about Valentine’s Day

B．advertise for USA Today

C．tell us that Americans are open to express love

D．sell roses on Valentine’s Day

进入受限空间时，（）应将所要求的表格和记录存放在现场。

A、项目负责人

B、审批人

C、监护人

在一定实验条件下，测得某植物光合作用速率与光照强度之间的关系（氧气浓度为15%）、呼吸作用速率与氧气浓度之间的关系及光合作用速率和呼吸速率与温度之间的关系如下图所示，请据图回答下列问题：

影响图甲中a曲线A点上下移动的外界因素主要是（）；图乙中细胞呼吸有关曲线的数据需在（）条件下测量。