請依下文回答第 46 題至第 50 題
 How an iceberg travels across the sea is sometimes unpredictable. When an iceberg breaks off from a glacier, itcan  __46__  for thousands of miles, traveling freely across the open ocean. But last week, an iceberg’s journey wasinterrupted when it got stuck on a __47__ part of the seafloor along Greenland’s western coast. In other words, the icebergwas grounded—and it had __48__ itself right beside the small island village of Innaarsuit. Such grounded icebergs areactually pretty common, says Fiamma Straneo, who has traveled about 20 times to Greenland’s ice sheet for her work atthe Scripps Institution of Oceanography at UC San Diego. What’s unique about the iceberg by Innaarsuit is both its sizeand its __49__ to the village. A grounded iceberg experiences ocean water pushing at it in one direction and the seafloorpushing in another—a __50__ that makes it easy for limbs to break off with a splash that can rock boats or flood coasts.The iceberg might even do an entire somersault in the water. Across the world, from the Canadian Arctic to Patagonia inArgentina, that shedding is both a tourist attraction and an issue of concern. The larger the iceberg, the larger the wavesit causes if it breaks apart.
【題組】46
(A) drill
(B) drizzle
(C) drift
(D) draft