Rob Howes wanted to spend a day at the beach．He（16）　　his daughter Nicky and her two friends，Helen Slade and Karina Cooper．They all went to Ocean Beach in New Zealand，where Howes was a lifeguard．

The group swam and bodysurfed．Then they saw something（17）　　．"Suddenly，there are these fins，"said Howes．

The（18）　　saw seven dolphins moving towards them．The dolphins seemed worried．They（19）　　the water with their tails．They kept moving in a circle around the swimmers．Then one large dolphin swam towards Howes and Helen．Next，it dived（潜水） down underwater．That's when Howes saw something grey moving in the（20）　　．

A great white shark（21）　　underwater．It wasn't far from the people．The shark headed straight towards Nicky and Karina．Now the shark was not slow．It moved（22）　　!So the dolphins used their tails to swim even faster．Each one splashed its tail even more．Then Howes knew （23）　　the dolphins did so．The dolphins didn't want to（24）　　him and the girls．These sea mammals（哺乳动物） wanted to keep them safe．

The dolphins stayed close to the group （25）　　the shark left．When Howes and the kids were safe，the dolphins swam away．

"You want to say thank you and shake their flippers，"Howes said．This isn't a fishy tale! These dolphins are heroes．

16．A．brought	B．missed	C．returned	D．searched
17．A．broken	B．common	C．strange	D．polluted
18．A．trainers	B．coaches	C．fishermen	D．swimmers
19．A．held	B．hit	C．cleaned	D．provided
20．A．pool	B．air	C．island	D．water
21．A．waited	B．washed	C．grew	D．served
22．A．beautifully	B．fast	C．heavily	D．away
23．A．where	B．what	C．why	D．whether
24．A．play	B．trust	C．harm	D．protect
25．A．until	B．because	C．if	D．since．