英语四级考试完形填空寒假练习（13）

　　Today, most countries in the world have canals.Many countries have built canals near the coast, and parallel____1____ the coast.Even in the twentieth century, goods can be moved more cheaply by boat than by any other ____2____ of transport. These ____3____ make it possible for boats to travel ____4____ ports along the coast without being ____5____ to the dangers of the open.Some canals, such as the Suez and the Panama, save ships weeks of time by making their ____6____ a thousand miles shorter.Other canals permit boats to reach cities that are not ____7____ on the coast, still other canals ____8____ landsswheresthere is too much water, help to ____9____ fields wherethere is not enough water, and ____10____ water power for factories and mills.The size of a canal ____11____ on the kind of boats going through it.The canal must be wide enough to permit two of the largest boats using it to ____12____ each other easily.It must be deep enough to leave about two feet of water ____13____ the keel of the largest boat using the canal.When the planet Mars was first ____14____ through a telescope, people saw that the round disk of the planet was criss-crossed by a ____15____ of strange blue-green lines.These were calledcanals ____16____ they looked the same as canals on earth ____17____ are viewed from an airplane.However, scientists are now ____18____ that the Martian phenomena are really not canals.The photographs ____19____ from space-ships have helped us to ____20____ the truth about the Martiacanals.

　　1.A.off B.with C.to D.by

　　2.A.way B.means C.method D.approach

　　3.A.waterways B.waterfronts C.channels D.paths

　　4.A.among B.between C.in D.to

　　5.A.revealed B.exposed C.opened D.shown

　　6.A.trip B.journey C.voyage D.route

　　7.A.lain B.stationed C.set D.located

　　8.A.escape B.drain C.dry D.leak

　　9.A.water B.wet C.soak D.irrigate

　　10.A.furnish B.afford C.offer D.give

　　11.A.focuses B.bases C.depends D.takes

　　12.A.cross B.pass C.move D.advance

　　13.A.down B.below C.beneath D.off

　　14.A.studied B.researched C.surveyed D.observed

　　15.A.few B.number C.deal D.supply

　　16.A.although B.because C.so D.if

　　17.A.that B.where C.when D.as

　　18.A.exact B.definite C.certain D.decisive

　　19.A.held B.taken C.got D.developed

　　20.A.find B.expose C.uncover D.discover