A．yourB．hisC．my
A. your
B. his
C. my
A．how oldB．how manyC．what
A. how old
B. how many
C. what
对于老人让年轻人捡起一粒沙的要求，年轻人觉得：
A. 又有趣
B. 太容易
C. 没意义
D. 不现实
Para. 4 mainly tells us
A. jatropha's bright future with its advantages.
B. jatropha's long history as a biofuel.
C. jatropha's advantages as a biofuel.
D. many cloned prolific varieties of jatropha in India.
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