题目内容：

Searching for airfares (飞机票价) often seems like a game that passengers are bound to lose.

Prices change from day to day, even minute to minute. Looking through multiple websites for the best deal can be a big challenge. Even when you do book, there’s no guarantee that you are going to get the best price.

“You just don’t know when to pull the trigger. It’s not like buying anything else I can think of,” said George Hobica, founder of Airfarewatchdog.com.

Harriet Levy paid $179 for a recent round-trip flight on American Airlines between New York and Fort Lauderdale, Florida. Sitting just one row behind her, Shirley Harrison paid $215. A few rows back, Ellis and Dianne Traub paid $317 each. There were at least 12 fares on the flight, ranging from $169 to $360.

There’s no reason for it, Harrison said.

Fares can fluctuate significantly in just a few hours. One Delta flight from New York to Los Angeles jumped from $755 to $1,143 from a Friday to Saturday in late April, then fell to $718 on Sunday.

The flight was one of a dozen the Associated Press followed over three months for a vacation between July 16 and 22. The number one finding: avoid booking tickets on weekends. It’s the most expensive time to buy.

There’s no way to guarantee the best fare. But before booking, travelers should pay attention to this additional advice:

? Book on Tuesday, Wednesday and Thursday. That’s when airlines most often offer sales.

? Buy in advance, but not too early. The best time is four to six weeks before traveling. In general, prices for any given flight are highest eight to 10 weeks and two to three weeks in advance.

? Make use of social media. Airlines are giving more benefits like exclusive (独家) sales to travelers who interact (互动) with them on Twitter and Facebook. Those specials are often gone within hours.

? The so-called discount (折扣) airlines – JetBlue, Air-Tran, Southwest and Frontier – adjust their fares less frequently than other airlines, so you can feel more confident that the price will stay the same. But their prices aren’t always the lowest. Researching multiple airlines’ fares is the only way to get a good deal.

1.What can we infer from the first sentence of the text?

A．Passengers are unable to search for airfares.

B．Airlines often play games with passengers.

C．Airfares are set in different situations.

D．It’s difficult for passengers to get the best price.

2.The underlined phrase “pull the trigger” in Paragraph 3 probably means _______.

A．start searching	B．get the highest price
C．make a purchase	D．get on board the plane

3.By using a lot of figures, the author intends to _______.

A．show there is standard price for every single airline

B．discover the rules behind airfares

C．guarantee passengers a low price

D．prove airfares can vary widely

4.Passengers are advised to book flights _______.

A．in the middle of the week

B．on special websites

C．several months before traveling

D．with airlines which are famous for offering discount prices