题目内容：

阅读理解。

Perhaps the most famous clothing brand name(服装品牌名称) in the world，Levi Strauss ＆ Co．is the inventor of blue denim jeans．Here’s how it happened．

In the mid-1800s many people went to California to look for gold．A young German named Levi Strauss traveled to San Francisco to help his brother on business．He sold canvas(帆布) to the workers for tents．But the workers said they needed pants more，because their pants were easy to wear out．Instead of selling his canvas for tent-making，he turned them into pants．These kinds of pants were very popular with workers．He was very happy and named the kind of pants“denims”．And in 1853 he founded Levi Strauss & Co．

Twenty years later the company began using a design with pockets．During the working，Strauss developed the process for putting metal rivets(铆钉) in the jeans for strength．

On May 20，1873，they received the U. S. Patent No. 139，121 for the process and that date is now considered the official birthday of“blue jeans”．

Today the company still has its factories in San Francisco，California．Over 11，000 people work in them and bring in over $4 billion a year．

1.Levi Strauss went to San，Francisco _______．

A．to look for gold

B．to sell canvas

C．to visit his brother

D．to help his brother on business

2.The workers often complained _______．

A．the canvas were not good

B．the work was too hard

C．they couldn’t get enough food

D．their pants were not strong enough

3.The underlined word“developed” may mean “______” in Chinese．

A．研制              B．想象

C．了解             D．确定

4.The blue denim jeans have about _______ years of history．

A．100                B．130

C．140                D．200

5.The passage mainly tells us _______．

A．who invented jeans

B．how jeans were invented

C．when jeans were invented

D．why jeans are so popular