A.the 4th
B.the 5th
C.the 6th
D.the 7th
延伸阅读
你可能感兴趣的试题
A.man and love
B.love and nature
C.man and nature
D.nature
A.Nature.
B.To Helen.
C.The Raven.
D.Annabel Lee.
A.5 November.
B.31 October.
C.17 March.
D.25 December.
A.Alaska
B.Sydney
C.Canberra
D.Perth
A.meaning shift
B.loss of meaning
C.widening of meaning
D.narrowing of meaning
A.16th
B.17th
C.18th
D.19th
A.Disappearance.
B.Untouchable.
C.Desirablity.
D.Physician.
A.Airborne dust may trigger suppressor macrophage suicides.
B.Airborne dust may trigger stimulatory macrophage suicides.
C.The ratio of suppressor macrophages to stimulatory ones in people with lung diseases is much higher than that in people with healthy lungs.
D.Only stimulatory macrophages show responses to airborne dust.
A.is the only agency studying the effects of air pollution on health
B.has launched a surprised attack on researchers
C.has decided to decrease the permitted concentration of airborne dust
D.has tremendously improved pollution control
A.many industrialists feel no concern for the improvement of pollution control
B.breathing low concentrations of urban dust does not necessarily sicken or kill people
C.no acceptable biological mechanism has been suggested to explain the toxicity of low concentration of urban dust
D.scientists have done nothing to reveal the mystery of the toxicity of low concentration of urban dust
热门相关试卷
最新相关试卷