Researchers are using an underwater drone (无人机) to get information on carbon dioxide (CO₂) levels in the ocean. It is believed to be the first time that such a device (装置) has been used purposely to test CO₂ levels.

The device, which the team also calls a glider, is designed to go down to 1,000 meters in deep ocean areas and can operate for weeks at a time.

The purpose of the research is to provide scientists with data (数据) about how climate change is influencing the ocean’s chemistry. The self-swimming drone was placed in the Gulf of Alaska this spring. Reporters from The Associated Press recently joined researchers on a boat in Alaska’s Resurrection Bay to see the drone in action.

The team says the project could be a major step forward in measuring(测量) the environmental health of oceans. The scientists are most interested in levels of ocean acidification(酸性). This happens when CO₂ emissions(排放) in the air make their way into the ocean. Ocean acidification can harm or kill some kinds of sea life.

Scientists have connected CO₂ emissions with global(全球) warming caused by human activities.

In a way, oceans have given humans a helping hand by taking in(吸收) some of the CO₂. If there were no oceans’ uptake, there would be much more CO₂ in the air. This would trap more of the sun’s heat and further warm the Earth.

“But the problem now is that the ocean is changing its chemistry because of this uptake,” said team member Claudine Hauri.

One of the best ways to measure ocean acidification is to collect CO₂ measurements. Until now, these collections were mostly done from ships or with devices floating at the ocean surface or on the ocean floor.

(1). What is probably this passage?

A．	An advertisement.	B．	Part of a news report.
C．	Part of a science fiction.	D．	A text from a chemistry textbook.

(2). What do we know about a glider?

A．	It must be used together with floating devices.
B．	It is used to measure ocean acidification.
C．	It is used to stop CO₂ from entering the ocean.
D．	It is used to measure CO₂ levels in the air.

(3). What does the underlined word “uptake” in Paragraph 6 most probably mean?

A．	The act of covering an area.	B．	The act of slowing something down.
C．	The act of taking something in.	D．	The act of killing or harming something.

(4). What is troubling the scientists?

A．	The underwater drone can’t swim by itself.
B．	The drone can only last one week at a time.
C．	Oceans are stopping taking in CO₂from the air.
D．	Too much CO₂ is making its way into oceans.