酒精灯的火焰分______三部分，温度最高的是______部分；熄灭酒精灯时不能用______，必须用______；给酒精灯添加酒精时，不准超过酒精灯容积的______； 不准向______的酒清灯里添加酒精．

点燃镁条的主要实验现象是______；该反应的文字表达式为______．

When asked about the secret about staying young, he said that a balanced diet __________ with exercise was the recipe for a healthy life.

A． conducted

B． concluded

C． combined

D．connected