一般认为圆锥型套筒冠义齿各固位体之间产生的固位力和最佳的范围是()
A.0.5~10kg
B.1.0~1.5kg
C.1.5~2.0kg
D.2~3kg
E.大于3kg
参考答案:C
中度高渗脱水( )|
A.失水量为体重的5%,血钠140mmol/L
B.失水量为体重的5%~10%,血钠130mmol/L
C.失水量为体重的10%以上,血钠138mmol/L
D.失水量为体重的10%以上,血钠129mmol/L
E.失水量为体重的5%~10%,血钠151mmol/L
Stem borers are insect pests that often ruin North American corn crops. On some other continents, crop damage by stem borers is controlled by a certain species of wasp. Since these wasps cat nothing but stem borers, importing them into North America will keep crop damage from stem borers under control without endangering other North American insect species. Which of the following is an assumption on which the argument depends
A.Corn is the principal food of stem borers that live on continents other than North America.
B.The wasps are capable of surviving in North America long enough to eat significant numbers of stem borers.
C.No wasp in North America is closely related to the species of wasp that eats stem borers.
D.On continents other than North America, the wasps control stem borers more effectively than does any other pest control measure.
E.(E) Corn crops on continents other than North America are not damaged by any insect pests other than stem borers.