Name: 一篇文章怎麼會有兩個或多個主旨？| 閱讀｜可汗學院 (How can a text have two or more main ideas? | Reading | Khan Academy)
Uploaded: 2021-01-14T10:58:50.000Z
Duration: 3 min 35 s
Description: 【看影片學英語】數萬部 YouTube 影片，搭配英漢字典即點即查，輕鬆掌握單字發音與用法，長久累積看電影不必再看字幕。

Today I wanna begin with a brief aside about physics.

Unless you're like a quantum particle or something,

it's not possible to be in two places at once,

nor is it possible to travel in two directions at once.

Right, if I'm on a train from Chicago to Pittsburgh,

I can't simultaneously be on a train from Chicago to Omaha.

So my body can't travel in two directions at once,

I know, it is possible to think two ideas at the same time,

but may not necessarily support one another.

it's hot outside and I'm late for my train,

and those two ideas can have equal weight in my mind.

or a book can have two or more main ideas.

It's a train that can go east to Pittsburgh

or what position are they trying to convince me of?

So how can there be room for more than one idea?

How can we tell that a piece has two main ideas

and not just one idea with supporting evidence?

All right, here's an example of two main ideas.

Sharks are deadly predators and fierce hunters.

They hunt with sharp teeth, incredibly sensitive noses,

and the ability to sense the electrical current

because encounters with them can be fatal.

because they are important to ocean ecosystems.

Their roles as high-level predators ensures

that they maintain population levels of smaller fish,

which in turn maintains the balance of ocean plant life.

If there were no sharks, algae could take over the ocean.

Now, both of these paragraphs are about sharks.

So in once sense, it's true that the passage

but what's the idea here in each paragraph?

Paragraph one says, "Sharks are deadly, and here is why."

And paragraph two says, "It's because of their deadliness

"because big predator species balance ecosystems."

These are two ideas that are separate but interrelated.

but they are two separate threads that each support

They are two distinct ideas here with equal importance.

When you're considering whether or not there

are two or more main ideas, ask yourself,

are both x and y equally important understandings

or is it just one idea supporting another?

you too can learn to travel in two directions at once

with the power of your mind and the power of reading.

♪ How can you be in two places at once ♪