Most plants can make their own food from sunlight, (1) some have discovered that stealing is an easier way to live. Thousands of plant species get by (2) photosynthesizing, and over 400 of these species seem to live by pilfering sugars from an underground (3) of fungi(真菌). But in (4) a handful of these plants has this modus operandi been traced to a relatively obscure fungus. To find out how (5) are (6) , mycologist Martin Bidartondo of the University of California at Berkeley and his team looked in their roots. What they found were (7) of a common type of fungus, so (8) that it is found in nearly 70 percent of all plants. The presence of this common fungus in these plants not only (9) at how they survive, says Bidartondo, but also suggests that many ordinary plants might prosper from a little looting, too.

Plants have (10) relations to get what they need to survive. Normal, (11) plants can make their own carbohydrates through photosynthesis, but they still need minerals. Most plants have (12) a symbiotic relationship with a (13) network of what are called my corrhizal fungi, which lies beneath the forest (14) . The fungi help green plants absorb minerals through their roots, and (15) , the plants normally (16) the fungi with sugars, or carbon with a number of plants sharing the same fungal web, it was perhaps (17) that a few cheaters—dubbed epiparasites—would evolve to beat the system. (18) , these plants reversed the flow of carbon, (19) it into their roots from the fungi (20) releasing it as "payment.\

13（）

A.large

B.vast

C.great

D.big

阅读理解。

     There are a lot of things that happen to me in China but would certainly never happen in the US. One of

those things is being called"strong".

     The first time was last December. I was walking across the high school campus in Guangzhou where I

taught when a student in a gray scarf waved hello. I smiled and waved back, but then she stopped and called

my name."You're so strong!" She smiled and pointed at what appeared to be my right arm.

     I looked down at my arms. Let's get one thing clear: I'm a very skinny guy. Once, while rehearsing for a

high school talent show, I was told by the teacher in charge that I couldn't participate in the men's shirtless

dance routine because my visible rib cage (胸腔) would frighten the audience.

     "I'm so what?""You're so strong!" she repeated."Um, thanks!" I didn't know what else to say, so we both

waved goodbye.

     The next morning I stepped into my oral English classroom only to be greeted instantly by a unanimous

(异口同声的) "Waaa!" of shock and admiration."What?" I asked."You're so strong!" shouted a boy from the

back of the class.

     "Okay, will someone tell me what that means?" I was curious as to the real reason for such praise. So I

turned to the monitor, gesturing for him to speak.

     "We just mean, you look very strong today," he offered earnestly.

     "What?! You mean like this?" I curled (卷起) my arm like a body-builder.

      "No! But it's so cold, and you're only wearing a short-sleeved shirt."

     Oh, I got it. My"strength" had less to do with my muscle and more to do with my apparent ignorance of

the cold weather.

1. From the passage we can learn that the author is _______.

A. an American teacher

B. an American student

C. a Chinese teacher

D. a Chinese student

2. The author used the example of being refused to join in the dance routine to show that ______.

A. many people worry about his bad health

B. actually he isn't physically strong at all

C. he is as strong as a body builder

D. being called "strong" often happens to him

3. The underlined word "she" in the 4th paragraph refers to ______.

A. a stranger he met on the way to work

B. the teacher in charge of the dance routine

C. the girl who joined in the rehearsing

D. the girl he met on the campus

4. Which of the following is the best title for the passage?

A. Am I Strong or Do I Need a Sweater

B. The Chinese Culture or the Western Culture

C. How I Can Get Stronger in Winter

D. How We Can Tell Two Different Cultures Apart