granger因果关系是什么?格兰杰因果关系是什么?看论文时常出现 不知有什么用处

In the Harry Potter films, Hermione Granger is better than her male friends and is considered the brightest pupil in her grade. Isn’t it often the same in schools of our real world? A great many boys fall behind their female classmates.
“It’s surprising but true that most of the top students have been girls since primary school. Girls are class leaders, club presidents and the top ones in exams,” said Wang Feixuan, 15, who studies at a Chengdu school. By any measure, Wang herself is a high-achiever. She is a top student, a team leader in her school’s sports club and a winner in national English and IT competitions.
But why do so many girls outperform their male peers（同辈）?
In Sun Yunxiao’s latest book Save Our Boys, he points out that the education system is “more suited to girls, who are good at memorizing and like to sit quietly and read.” Yet he also says that girls have to do so much more when they compete with males for honors, top universities and later good jobs. They can feel great pressure（压力）nearly every day.
This seems to be the same in most countries in the world. Young women in the United States are also reported to feel the same pressure to be perfect.
“Let’s look at what we ask of our teenage girls,” says an American professor Stephen Hinshaw in an interview.
He thinks that it’s no longer enough that a girl does well in school and is a caring friend. On the TV, on the Internet, and everywhere, girls see images of impossible perfection（完美）.
Today’s young women must be good learners, good athletes, and fill their after-school lives with other activities. But they’re also asked to have the styles and looks of popular stars. “Be pretty, sweet and nice. Be athletic, competitive and get straight. Be impossibly perfect.” Stephen Hinshaw sums up.
小题1:The passage suggests that________.

A．our society asks far too much of teenage girls

B．teenage girls shouldn’t be so perfect at school

C．boys are always lazy ones rather than girls

D．American girls have less pressure than Chinese girls

小题2:According to the passage, it is true that .

A．boys are less smart than girls throughout school life

B．boys usually don’t have so much pressure as girls do

C．girls are all fond of the Chinese education system

D．girls are better at school because boys don’t work hard

小题3:The underlined word outperform means_________.

A．mistake

B．misunderstand

C．ignore

D．defeat

小题4:What’s the best title for the passage_________?

A．Impossibly Perfect Is Possible.	B．Why Are Girls So Perfect?
C．Perfect? Pressure Every Day!	D．Perfect: Boys or Girls?