题目

Dangerous as they are, extreme sports remain appealing among many Australian young people! Camp Xtreme is the perfect test of your heart.Kite SurfingIt’s the exciting mixture of kite, board and waves. The idea of using a kite to accelerate speed seems like a new challenge, yet the art of kite flying dates back to the 13th-century Chinese whenitwas used as a simple means of transport.Catch a wind and you’re moving — up, down and across the surf. “It’s always exciting. You’d jump 5 feet or 35 feet. You never know if you’re going to go up in the air, and your heart is just going boo3．以下物质由离子构成的是（　　）A．矿泉水B．氯化钠C．金刚石D．氧气