单选题：完成题　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 DForty—thousand o

完成题　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 D
Forty—thousand of the world’ s young children die every day．Many of these deaths can be prevented．In fact，experts say，techniques now exist to save the lives of half of these children．The techniques are medically effective(有效的)，simple to use and low cost.The biggest task has been to inform parents about these life-saving techniques．
Diarrhea(腹泻)is the main cause of death among children in developing countries．Diarrhea results when the body tries to clear itself of harmful bacteria(细菌)．The body does this by getting our liquids，sometimes uncontrollably．If too much water，sugar and salt ale lost in this way，the body cannot work normally．The child may die．
The Uni ted Nations International Children’s Fund，UNICF，introduces a technique．It uses a simple mixture of sugar and salt in water．The mixture does not stop diarrhea．But if used often as needed，it keeps fluid(体液)levels normal until the body has fought off the harmful bacteria．
In Egypt，for example，the treatment was used in a children’s health care program in the province of Alexandria．It reduced by one—half the number of deaths caused by diarrhea.The technique has now been used throughout the country．

According to the passage，a large number of Children can be saved only when________． A．the life—saving ways are medically effective
B．their parents are rich enough for the life—saving techniques
C．rite life—saving techniques are easy to use
D．their parents learn the life—saving techniques