阅读“七选五”训练
根据短文内容，从短文后的选项中选出能填入空白处的最佳选项，选项中有两项为多余选项。
Using a Mobile Phone to Improve Mother and Child Health
People around the world are working to expand the uses for mobile technology in health care.
In the world, there are six billion mobile phone users in a population of seven billion people.
36 Africa has widespread use of mobile phones. Three or four years ago the penetration（进入市场）rates were 20 percent or 30 percent, and now they're getting upwards of 60 percent in some countries.
37 Earlier research has been conducted to look at mobile technologies and HIV and AIDS. And so we have some great evidence on the effectiveness of mobiles.
