The San Diego Zoo has been a lovely home for giant pandas since two of the black-and-white bears came to visit in 1987．This week there was snow in San Diego-well，at least for a lucky group of giant pandas．

Over 15tons of snow was blown into the San Diego Zoo's panda area on Tuesday morning to give the endangered bears a chance to play．They would experience the snow just like living in their natural habitat．

The snow day was a first for Xiao Liwu whose name means"Little Gift．"He was the sixth baby panda born to Bai Yun．Xiao Liwu was jumping on Mom，playing with her and getting used to being thrown in the snow by mama bear．Jennifer Becerra，San Diego Zoo keeper said，"He was really enjoying the snow and running around．I've never seen him so happy．"

All the San Diego Zoo's giant pandas are from China，as part of a long-term captive breeding（人工养殖） program．Four of Xiao Liwu's brothers have already been moved from California to China．

Today there are 44giant pandas living in zoos outside of China，where the bears'only natural home is．As just 1，600pandas are thought to be left in the wild，researchers insist that captive breeding is an important way to study and protect the endangered pandas．Not only because of the habitat loss from human activities and low reproductive rates（繁殖率），giant pandas'survival is also affected by climate change．A study showed that global warming could kill much of the bears'main food，bamboo，over the next century．

36．Why was the snow blown into the San Diego Zoo's panda area？___

A．To stop the bamboos from dying．

B．To give the pandas a chance to play．

C．To help the pandas live in their natural habitat．

D．To make Xiao Liwu happy．

37．What's the relationship between Bai Yun and Xiao Liwu___？

A．Wife and husband．

B．Father and daughter．

C．Sister and brother．

D．Mother and son．

38．What is NOT the factor t