1 . Scientists from the University of Texas at Austin have finally solved the mystery of a huge fossil(化石）that has been unlabeled and unidentified sitting at a Chilean museum for almost a decade. The relic which looks like a flat football, is the largest known soft-shelled egg from a marine reptile（海生爬行动物）that lived on the earth over 66 million years ago. Measuring more than 11 by 7 inches» it is also the second-largest egg belonging to any known animal, only behind the now-extinct elephant bird.

The rare fossil named " The Thing" was discovered inside a rock formation in Seymour Island off the coast of Antarctica in 2011 by a team of researchers including David Rubilar-Rogers. Over the years, the paleontologist（古生物学者）at Chile's National Museum of Natural History has showed the strange fossil to every geologist that came to the museum. However, no one was able to identify “The Thing's" origin until Julia Clarke» a professor at UT-Austin's Jackson School of Geosciences, visited in 2018.

“I showed it to her, and, after a few minutes, Julia told me it could be an egg!" Rubilar-Rogers said.

To confirm Clarke's suspect, Lucas Legendre, a student at UT-Austin who led the study, examined the fossil under a microscope. Sure enough, he found several layers of membrane（薄膜），confirming that the fossil was indeed a soft-shelled egg, similar to the obvious, quick-hatching eggs laid by some modern-day snakes. “The shell is very thin,” said Clarke.

The fossil's identification led to an even bigger mystery—what animal could have laid an egg this size? After considering several potential parents, the researchers concluded that the egg was laid by an ancient marine reptile like a masseur（沧龙）. The fact that the rock formation where the egg had been found had fossil evidence of baby masseurs and the offspring of other marine animals further strengthened their theory.

1. What can we know from the first paragraph?

A．“The Thing” is the largest egg laid by animals.

B．“The Thing" has been discovered for a century.

C．“The Thing” looks like a football not having enough gas.

D．“The Thing” belongs to an elephant bird.

2. What is Clarke's guess about “The Thing”？

A．It may be laid by a snake.

B．It could be an egg.

C．It has a very thick shell.

D．It has existed for 66 thousand years.

3. How did Legendre test Clarke's guess?

A．By comparing the fossil with the eggs of various animals.

B．By analyzing a lot of data collected by researchers.

C．By doing many experiments with his colleagues.

D．By using a microscope to examine "The thing"・

4. What does "their theory" in the last paragraph refer to?

A．The egg's potential parents are snakes・

B．An ancient marine reptile laid the egg.

C．The size of the eggs lies in the weight of the animals.

D．The way of rock formation affects the egg.