已知函数$f\left(x\right)=\frac{1}{\sqrt{1-x}}$的定义域为$A,g\left(x\right)=\ln x$的值域为B，则$A\cap B=$（  ）

小李的父亲在读中学时，学校停课闹革命，他参加了红卫兵，这样的事发生在（    ）

    Some people think that as more and more people have televisions in their homes, fewer and fewer people will buy books and newspapers. Why read an article in the newspaper, when the TV news can bring you the information in a few minutes and with pictures? Why read the life story of a famous man, when a short television program can tell you all that you want to know?

    Television has not killed reading, however. Today, newspapers sell in very large numbers. And books of every kind are sold more than ever before. Books are still a cheap way to get information and enjoyment. Although some books with hard covers are expensive, many books are printed today as paperbacks (平装本), which are quite cheap. A paperback collection of short stories, for example, is always cheaper than an evening at the cinema or the theater, and you can keep a book for ever and read it many times.

    Books are a wonderful provider of knowledge and pleasure and some types of books should be in every home. Every home should have a good dictionary. A good encyclopedia, though expensive, is useful, too, because you can find information on any subject. Besides, you can have such books as history books, science textbooks, cookbooks, and collections of stories and poems. Then from time to time you can take a book of poems off your shelves and read the thoughts and feelings of your favorite poets.

△ABC中，∠C=90°，AB=8，cosA=$\frac{3}{4}$，则AC的长是____ 。