$\frac{8}{9}\times \frac{5}{16}+\left(\frac{7}{16}-\frac{1}{4}\right)÷\frac{1}{2}$ =____

阅读短文，然后从方框中选出可以填入文中空白处的单词

All  drinking discovered  besides  pick According to during  green most  first

Chinese tea

Tea is the ____ popular drink in the world ____ water. ____ tea comes from the tea plant. People ____ leaves from it to make tea.

The habit of ____ tea has a long history in China. ____ an old story , Chinese Emperor Shennong ____ tea. Lu Yu, a writer ____ the Tang Dynasty, wrote the ____ book about tea.

There are several types of Chinese tea, such as white tea, ____ tea and black tea.

如图,圆O的直径AB=8,C为圆周上一点,BC=4,过点C作圆的切线l,过点A作直线l的垂线AD,点D为垂足,AD与圆O交于点E,则线段AE的长为____.