题目内容：

-American office workers spend an average of 52 hours a week at their desks, according to a statistic survey. Some might argue that not all that time is spent working，but still all those hours in windowless offices with artificial light can have an influence.

A few green additions could have a large effect on worker happiness，according to the survey led by Tina Cade from Texas State University.

“We pretty much found out that if you had windows and plants or even if you just had plants in your office, you were more satisfied with your job,” Cade told LiveScience. “We thought it was important for offices because a lot of times people are looking for ways to keep employees happy and do all these expensive things like building a gym. Maybe for less investment they could put in a few plants in important places.”

The team surveyed 450 office workers in Texas and the Midwest，asking questions about job satisfaction and the work environments. When asked about their overall life quality,82 said they felt “content” or “very happy”. Only 69 percent of those who work with plants but without windows，and 60 percent of those who have windows but no plants, said they felt this way.

The group of people who work without plants or windows were  the most dissatisfied，with only 58 percent of them saying that overall they were “content” or “very happy”. While no one who works with plants，windows，or both reported they felt “miserable”, 0.8 percent of those who work in offices without either said they were “miserable”. “I was really surprised that having a plant in your office appeared to be more beneficial than having a window in your office,” Cade said. “Everybody says, ‘I need a window!’ but actually it seemed like a plant could be a suitable alternative.”

1.What does the passage mainly tell us?

A．Green plants can increase job satisfaction.

B．An easier way to increase job satisfaction.

C．What the best working environment is.

D．Who are happy with their job environment.

2.Among the 450 people surveyed, ________.

A．69 percent have plants in their offices

B．60 percent have windows in their walls

C．0.8 percent of them feel dissatisfied

D．about 18 percent of them are satisfied

3. According to the survey，the group of people who work without plants or windows ______.

A．didn’t feel content at all

B．all suffered from work pressure

C．were the most dissatisfied

D．worked with low efficiency

4. Which of the following statement is true?

A．The employers want to do little to keep employees happy.

B．Sometimes it doesn’t need much to increase job happiness.

C．A gym contributes less to job happiness than green plants.

D．Employers have tried every means to increase job happiness.