Bees and other pollinators（传粉者）  use smells to track down fresh flowers. Air pollutants can weaken those scents（气味）.  Scientists had worried this might make it harder for some pollinators to find a meal.

    Many animals help pollinate plants. Species that do this include bees, butterflies, etc. But for many reasons, the pollinators available to help plants in this way are decreasing. Scientists think a loss of habitat（栖息地）can be one factor. Diseases and exposure to poisonous chemicals also count.

    Jose Fuentes points to air pollution as another possible factor. He's an atmospheric scientist at Pennsylvania State University. In an earlier study, he showed some air pollutants could weaken or destroy scents emitted(发出)by flowers.

    Searching for a meal leaves pollinators out in the open and at risk of becoming other animal's lunch. And any time spent hunting food is time away from their duties back home, like protecting a hive（蜂巢）or nest, explains T'ai Roulston. He's an insect biologist at Virginia University. Roulston worked with Fuentes on the new study.

    In the study, the researchers focused on five kinds of representative scent molecules(分子)plants emit. One molecule they looked at, for example, is called beta-myrcene. Many flowers give off this chemical into the air.  Normally, this gas can travel some 800 meters from its flower source. But in polluted air, this same molecule could travel only half as far.

    Worse still, air pollution might do more than just weaken scent plumes（气味烟云）．Chemical reactions between air pollutants and plumes may transform the flowers' smells, creating new scents. And these scents may be unrecognizable to pollinators.

    That's certainly Fuentes' concern.  So, he says his next research project will look at how insects handle any new flower scent. "It's possible that some insects will change ways to detect and use these new molecules to find food," he says.

    To be more grateful (感恩的) in life means that you are also allowing yourself to be happier and more satisfied with everything that has been going on around you. But with all the stress, all the disappointments and all the anxiety around you. I bet you ask yourself this question all the time: “How exactly can I be more grateful with my life?”____.

    ⒈ Learn to live in the moment.

    Life is a wonderful adventure full of enriching experiences and endless possibilities. Don't just go through the motions of (走过场) repetitive(重复乏味的) activities and boring tasks. No! Being a mindless zombie (行尸走肉) can make you more likely to take things for granted (对……不予重视).____, make an effort to enjoy the experience.

    You're supposed to attend a conference? Absorb it. Babysit your niece? Enjoy the moment. Eat a 15-minute lunch? Taste each bite.

    ⒉____

    Being aware of your goal to be more grateful can help you look for things to be really more grateful for. Gratitude is a conscious decision. You have to practice it consistently (持续的，始终如一地).

    ⒊ Control your thoughts.

    Of course you have the power to control what you're thinking of! Consider this exercise, for example: if you find yourself thinking more and more self-entitled (自我为中心), stop.____. You are given consciousness (意识). Make use of it wisely.

    ⒋Always resist the temptation (诱惑) of comparing yourself with other people.

    As humans, we have the natural tendency (倾向、偏好）to compare ourselves with others with the hope of attaining satisfaction. Actually, this kind of activity does not help you feel to be more grateful in life.____! You will always be meeting someone richer, which makes you fed inferior (下等的) to others!

    Don't do it, please.

    Every little thing counts. You have the ability to make yourself feel to be more grateful in your life.

A. Appreciate what you had in the past

B. And if you find yourself repeating negative (消极的) junk, stop

C. It does the opposite

D. Express gratitude all the time

E. Well, the following are some tips to help you with this particular concern (忧虑)

F. Instead of doing something just for the sake of (为了) doing it

G. Words that stress you and make you feel worthless should definitely be removed

My father came back while I was having dinner.