English is the most widely used language in the history of our planet. One in every seven human beings can speak it. More than half of the world's books and three quarters of international mail are in English. Of all languages, English has the largest vocabulary — perhaps as many as two million words.

    However, let's face it: English is a crazy language. There is no egg in an eggplant, neither pine nor apple in a pineapple and no ham in a hamburger. Sweet-meats are candy, while sweetbreads, which aren't sweet, are meat.

    We take English for granted. But when we explore its paradoes (探索它的矛盾), we find that quicksand can work slowly, boxing rings are square, public bathrooms have no baths in them.

    And why is it that a writer writes, but fingers don't fing, grocers don't groce, and hammers don't ham? If the plural of tooth is teeth, should't the plural of booth be beeth? One goose, two geese — so one moose, two meese?

    How can a slim chance and a fat chance be the same, while a wise man and a wise guy are opposites? How can overlook and oversee be opposites, while quite a lot and quite a few are alike? How can the weather be hot as hell one day and cold as hell the next?

    English was invented by people, not computers, and it reflects the creativity of human beings. That's why, when stars are out, they are visible (能看见的); but when the lights are out, they are invisible. And why, when I wind up my watch, I start it; but when I wind up this essay, I end it.

In the past decade ocean oxygen levels have taken a dive — an alarming trend that is linked to climate change, says Andreas Oschlies, an oceanographer at the Helmholtz Center for Ocean Research in Germany, whose team tracks ocean oxygen levels worldwide. "We were surprised by the intensity of the changes we saw, how rapidly oxygen is going down in the ocean and how large the effects on marine ecosystems are," he says. It is no surprise to scientists that warming oceans are losing oxygen, but the scale of the drop calls for urgent attention. Oxygen levels in some tropical regions have dropped by an astonishing 40 percent in the last 50 years, some recent studies reveal. Levels have dropped less significantly elsewhere, with an average loss of 2 percent globally.

A warming ocean loses oxygen for two reasons; First, the warmer a liquid becomes, the less gas it can hold. That is why carbonated drinks(碳酸饮料) go flat faster when left in the sun. Second, as polar sea ice melts, it forms a layer of water above colder, more salty sea waters. This process creates a sort of lid that can keep currents from mixing surface water down to deeper depths. And because all oxygen enters the surface, less mixing means less of it at depth.

Ocean animals large and small, however, respond to even slight changes in oxygen by seeking refuge(避难所) in higher oxygen zones or by adjusting behavior, Oschlies and others in his field have found. These adjustments can expose animals to new predators or force them into food-scarce regions. Climate change already poses serious problems for marine life, such as ocean acidification, but deoxygenation is the most pressing issue facing sea animals today, Oschlies says. After all, he says, "they all have to breathe."

Aside from food web problems, animals face various other physiological challenges as their bodies adjust to lower oxygen levels. Chinese shrimp(虾) move their tails less vigorously to preserve energy in lower oxygen environments. Some creatures, such as jellyfishes, are more tolerant of low oxygen than others are. But all animals will feel the impact of deoxygenation because they all have evolved their oxygen capacity for a reason, says Oschlies. "Any drop in oxygen is going to damage survivability and performance," he says.