三、克漏字測驗【請依照段落上下文意，選出最適當的答案】
       Have you ever visited the beach? Did you recall seeing a man with a headset pointing a long pole at the ground?If the answer is affirmative, you might have seen a person using a metal detector. People use these __26__ to finda variety of metals. Metal detectors emit magnetic waves which go through the ground. The waves change whenthey hit metal, and the device beeps. This enables the person with the device to know that some sort ofmetal is __27__ .
       The first metal detectors were meant to help miners. In the old times, the devices were big and cost a lot ofmoney. Moreover, they __28__ a lot of power. Worst of all, they didn’t work well. Later, people kept trying tomake such devices better. With much effort, metal detectors got smaller. Today, they are light and cheap, and theycan work effectively. That is why people bring them to the beach. Metal detectors help people find lost items, suchas rings lost in the water or phones buried in the sand. However, very often, such a search is __29__ and theworkers only find junk. In addition, metal detectors protect people. They help to __30__ guns out of some places,like airports, courthouses, or even schools. Guards use special wands, functioning as metal detectors, to find if thereis any metal on a person. Evidently, these devices have become very helpful in modern-day lives.
【題組】26.
(A) devices
(B) pools
(C) ear sets
(D) movements