Directions:Read the text below. Use the word at the end of each line to form a new word that fits in the space in the same line. 下面的短文有11处空白，每处空白后的括号内有一个词，请根据短文内容将其正确的形式填入，以恢复文章原貌。Crude OilAlthough crude oil is still(40)____________(vast)available in the earth’s crust, it is not a/an(41)____________(finite)resource. At some point it will eventually be(42)____________(exhaust). The demand for crude oil has increased by gigantic proportions. However,(43)___________(discovery)of new oil fields and investing in the oil industry have helped keep up with the(44)____________(increase)demand for oil. The crucial question is, how long will the oil resources last?(45)____________(advance)technology has made drilling oil more(46)____________(effect)and efficient. With the aid of new methods it is possible to draw almost 65% of the oil as opposed to the old methods. Better infrastructure and more(47)____________(invest)have also made the drilling of oil wells more effective. Currently most(48)____________(transport)is dependent on oil and many industries are born out of or lean on byproducts of petroleum. Although alternative sources of energy are now(49)____________(apply),like solar and wind energy, it is still a long way to be completely(50)____________(dependent)of crude oil.40. ____________