課本中不會教你的[R]568　rate，ratio，speed和velocity

568　rate，ratio，speed和velocity

① rate表示速度、比率等。

I read at a rate of 150 words a minute. 我每分鐘閱讀速度為150個詞。

The interest rates of the state bank have been lowered six times recently. 國家銀行的利率最近下調(diào)了六次。

② ratio表示比或比率，不表示速度。

The ratios of 1 to 5 and 3 to 15 are the same. 1與5之比同3與15之比相等。

③ speed是沒有方向的速度，行駛速度。

The two trains didn't lower their speed along the rails when running in opposite direction. 這兩列火車在相反方向沿鐵軌行駛的時候沒有減速。

④ velocity是技術(shù)術(shù)語，帶方向性，也表示極高速。

The velocity of a missile is controlled from thousands of miles away. 火箭的速度在數(shù)千英里以外加以控制。

The two cars clashed and crashed with great velocity. 兩輛高速行駛的汽車被撞得粉碎。