皂荚树利用光能，把二氧化碳和水在叶绿体中合成淀粉等有机物并储存能量过程叫（）
A.光合作用
B.呼吸作用
C.蒸腾作用
D.扩散作用
参考答案：A
If _________, the bird flu would produce a powerful poison that would kill the patients.
A. not treat B not treated C untreated D. Both B and C
Which is a disadvantage of Halon as a fire extinguishing medium?（）
A.Conducts electricity
B.Difficult to store
C.Large volume necessary to be effective
D.Ineffective in powdered metal fires
