语法与词汇The gravitational attractive of a black hole is extremely intense, but it would be no stronger ___ of a normal star of the same mass.
语法与词汇The Buffalo River in Arkansas was designated ______ in 1972.
语法与词汇The United States government shares governmental powers with the states under the federal system.---- by the United States Constitution.
语法与词汇The economic (heart) of Canada, Ontario (accounts for) more than 40 (percentage) of the nation''s productive (capacity).
语法与词汇Saturn takes almost 30 Earth years (to make) one trip around the Sun, (during) Jupiter takes about twelve Earth years (to complete) one solar (revolution).
语法与词汇____ Earth's crust averages only 004 grams of the gold per ton, .........."?
语法与词汇From colonial times, United States property owners agreed to tax themselves on the theory ________ directly from services that the government could provide.
语法与词汇When changes in the tilt of the Earth relative to the Sun shift the location of South America's warmest zone,---- with it.
语法与词汇(Children) use (grammatically correct) sentences by (the age) of three and (produces) some highly complex construction by the time they are five.
语法与词汇The United States Congress appropriates some four million dollars_______ the upkeep of the White House grounds.
语法与词汇In eighteenth-century North American, printed engravings provided____ rococo style.
语法与词汇__________ land and money enabled construction of the Union Pacific railroad to begin from Council Bluffs, Iowa, in 186
语法与词汇Fossil remains (reveal that) the farther back in time (an animal) lived, the smaller (than was) its brain in (proportion) to the size of its skull.
语法与词汇The museum on Ellis Island, a former immigration station, contains documents and artifacts_________ to four centuries of United States immigration.
语法与词汇Astronomers estimate ______called the Pleiades in the constellation Taurus is 415 light-years away from Earth.
语法与词汇Inertial navigation,---- a vital role in space exploration, employs devices called accelerometers to measure accelerations of spacecraft.