The world's hottest rainforest is located not in the Amazon or anywhere else you might expect，but inside Biosphere （生物圈） 2，the experimental scientific research facility in the desert outside Tucson，Arizona.A recent study of tropical trees planted there in the early 1990s reported a surprising result：They have withstood temperatures higher than any likely to be experienced by tropical forests this century.
   The study adds to a growing number of findings that are giving forest scientists something that's been in short supply lately：hope.Plants may have unexpected resources that could help them survive - and perhaps even prosper - in a hotter，more carbon-rich future.And while tropical forests still face both human and natural threats，some researchers believe terrible reports of their approaching decline due to climate change may have been overstated.
   "Biology is clever，" says Scott Saleska，an ecologist at the University of Arizona in Tucson and co-leader of the Biosphere 2 study. "It's a lot smarter than our models yet represent."
   The last few years have seen a flood of alarming reports about forests and climate change's effects on them.Scientists have announced that the Amazon forest is no longer a reliable carbon sink；the Amazon rainforest may be nearing a tipping point；tropical forests globally are already close to the hottest temperatures they can tolerate and climate change is killing off old trees.
   One thing is certainly true：Our fossil fuel emissions are creating a climate that humans have never seen and trees haven't experienced in a very long time."We're pushing tropical forests into temperatures they've never seen since the Cretaceous - since there were dinosaurs，" says Abigail Swann，an ecologist and climate scientist at the University of Washington in Seattle.

（1）Where is the hottest rainforest located according to the article？

B

B

A．In the Amazon tropical forest.
B．In a research facility in Arizona.
C．In the rainforest in Brazil.
D．At the University of Arizona.
（2）What can we conclude from the second paragraph？

C

C

A．Forest scientists still lack numbers of findings about rainforest.
B．Plants may not survive in hot and carbon rich future than expected.
C．Plants may survive in hotter and more carbon-rich environment.
D．People may overstate the climate change in the future.
（3）How will the fossil fuel emissions change the climate？

C

C

A．We have never seen the climate change due to greenhouse.
B．The fossil fuel emissions may destroy the whole ecosystem.
C．The temperatures may reach as high as those in dinosaur period.
D．The fossil fuel emissions may create a climate plants can't bear.
（4）What may be the best title of the article？

D

D

A．The world's hottest rainforest in the wild
B．Plants may die of fossil fuel emissions due to mankind
C．The Amazon forest is declining quickly in the future
D．Plants may stand hotter temperature than expected