息，並對這些變化作出回應。
strain［strein］n。 拉力；扭傷；菌株 v。 扭傷；使緊張；拉緊
搭配 strain one's shoulder 扭傷肩膀
例句 1。 The deadliest strains of the virus perished with their hosts simultaneously as natural selection favored strains that could infect hosts but not kill them。 最致命的毒株與它的寄主一同死亡，因為自然選擇更偏向那些能使寄主感染，而不是殺死寄主的菌株。
2。 Genetic engineering also may supply a partial solution； as new strains of drought…resistant crops continue to be developed。 隨著抗旱作物的新品種被繼續培養，遺傳工程也許會提供一個不完全的解決方案。
同義 sprain（n。/v。 扭傷）
suppress［s？'pres］v。 抑制，阻止
例句 1。 If the theory was correct； breathing air with extra carbon dioxide