16．There are many kinds of food in the world．Scientists learn a lot about them．（51）CFor example，people must eat some green and yellow vegetables．We shouldn't eat too much meat．（52）EOf course our bodies need some water and milk．
Scientists say people in different countries and different places eat different kinds of food．（53）A Different people eat at different times．In one place，people eat once or twice a day．（54）D The scientists say when to eat and how many times to eat are not important．What we eat is the most important thing．
Nowadays，the world faces two problems．People in some places，for example，in Africa，are not full．Many people are eating junk food．（55）B So it's our duty to make everyone full and make everyone healthy．
A．They cook food in different ways．
B．It's bad for people's health．
C．They say that there are some kinds of food people must eat every day．
D．But in another place，people eat three or four times．
E．People also need to eat some fruits，bread and．rice．
