3．What does the underlined phrase "at sea" probably mean?

　　A．Tired. B．Disappointed.

　　C．Pleased. D．Confused.

　　解析：选D　词义猜测题。根据画线短语后的一句话可知，这三位外国人对英国的风俗并不知情，由此可知，当他们面对英国人当时的反应时会感到迷惑。

　　4．In India it is considered impolite to________.

　　A．use the right hand for passing food at table

　　B．pass food with the left hand

　　C．eat food with your hands

　　D．help yourself at table

　　解析：选B　细节理解题。由第二段的"A visitor to India would do well ... left hand for passing food at table."可知，在印度用左手递食物被认为是不礼貌的。

　　B

　　Car companies such as Tesla and Nissan have been leading the way in electric car technology. What makes these cars "green" is that because they run on electricity instead of gasoline, they do not give off any polluting greenhouse gases. The Toyota Mirai is also a kind of green car, since it is powered by a hydrogen fuel battery (氢燃料电池)．

　　Hydrogen, as you know, exists in large quantities on the earth. It was used to power gaslights for centuries before electric lights came along. Hydrogen fuel can be made from many sources including solar, natural gas and even rubbish. In terms of energy contained, 9.5 kg of hydrogen is equal to 25 kg of gasoline. According to Toyota, the two tanks on the Mirai hold 5 kg of hydrogen, and can cover a distance of over 300 miles. This is twice the output of gasoline cars.

　　In a hydrogen fuel battery, the one proton (质子) and one electron in a hydrogen atom are broken up. While the electrons power the car, the positively­charged hydrogen proton combines with the oxygen atom to produce water. The process also produces a lot of heat which turns this water into water vapor. This is the reason that cars running on hydrogen fuel batteries give off water vapor from their exhaust pipes when running.

　　According to Toyota, it takes only 5 minutes to refill a hydrogen tank, which is much quicker than charging electric cars. However, the biggest challenge for the company is the availability of hydrogen­charging stations. California and the New England states are in the process of building a hydrogen superhighway - with charging stations along the way. Countries like Germany, Japan and the UK are also adding more charging stations.

The Toyota Mirai began to be available in the US in the second half of 2015 for $57,500. This hydrogen­fueled car will probably take the place of gasoline cars in the near future. After all, it is an energy­saving and environment friendly car.