7 . Have you ever been in a bathroom, dressing room or another private area with a mirror and had that feeling that someone is watching you? You can check to see if a mirror is transparent by observing how it is installed and using a few simple techniques to determine if there’s a wall behind it.     1    

Check out the lighting. For a two-way mirror to be effective, the light on the mirrored side needs to be 10 times brighter than the light on the other side. If the lighting is dimmer, it’s possible to see through the glass to the observation area. Look around and determine whether the lighting seems extraordinarily bright.     2    

    3    Press your face up to the mirror and cup your hands around it, creating a dark tunnel to block out as much light as possible. When you do this, if the light in the observation room is at all brighter than the light on your side of the mirror, you should be able to see something through the glass.

Sound it out. The sound of tapping a two-way mirror has also been described as bright or sharp as opposed to a thud (砰的一声) from an everyday mirror. Tap on the surface of the mirror with your knuckle (指节).     4    An observation mirror will produce an open, hollow and echoing sound because there is an open space on the other side.

    5    Then hold a flashlight to the mirror (it can be the “flashlight” on your smartphone). If it is a two-way mirror, the room on the other side will be illuminated and you’ll be able to see it.

10 . Here is a story about a young boy in New York. He once went to one of Dr. Jane Goodall’s talks and learned about the _______ expressions of chimpanzees.

When he saw a picture of a chimpanzee on a box of _______and it looked like the chimpanzee was grinning (咧嘴笑), the boy _______ from what he’d learned at Dr. Goodall’s talk that the chimpanzee’s look was actually one of _______.

The boy _______ to the cookie-maker asking to take the chimpanzee’s picture off the box. _______ receiving a letter back from the company, he saw the picture of the chimpanzee _______from the box within just a few months.

“I took _______,” the boy now says. “And the company changed.”   _______ it happened that the picture changed, the boy and his family   ________it was his doing.

As the story shows, young students have much more ________ to accomplish change than what   ________may believe. Moreover, students often achieve much more than they ever   ________ they will.

The story also ________us that small actions can have a big impact. We often tend to think about   ________ events like Clean and Green Week. Instead, a lot of small changes can make a(an)   ________. If hundreds or thousands of students   ________ their families to turn off the tap to save water, move the air-conditioning temperature up a degree or two, drive less and make other environmentally friendly changes, the ________ family may change its behaviors.       

With these small yet highly   ________ changes, students have an effect beyond just their own actions. Students can   ________ by realizing that their own actions have more power than they may expect, and environmentalists can benefit as well by taking the time to focus on even the youngest students.