There was a time when parents who wanted an educational present for their children would buy a typewriter, a globe or an encyclopedia set. Now those (21) seem hopelessly old-fashioned: this Christmas, there were a lot of (22) computers under the tree. (23) that computers are their key to success, parents are also frantically insisting that children (24) taught to use them on school— as early as possible.The problem for schools is that when it (25) computers, parents don’t always know best. Many schools are (26) parental impatience and are purchasing hardware without (27) educational planning so they can say,"OK, we’vr moved into the computer age. "Teachers (28) themselves caught in the middle of the problem — between parent pressure and (29) educational decisions.Educators do not even agree (30) how computers should be used. A lot of money is going for computerized educational materials (31) research has shown can be taught (32) with pencil and paper. Even those who believe that all children should (33) to computer warn of potential (34) to the very young.The temptation remains strong largely because young childrern (35) so well to computers. First graders have been (36) willing to work for two hours on math skills. Some have an attention span of 20 minutes. (37) school ,however, can afford to go into computing, and that creates (38) another problem: a division between the have’s and have-not’s. Very few parents ask (39) computer instruction in poor school districts, (40) there may be barely enough money to pay the reading teacher. 31().
A. are
B. be
C. are being
D. were
下列对于二元算术运算表达式的说法中,正确的一个是______。
A. 若两个操作数都是float型,则表达式结果为float型
B. 若两个操作数都是float型,则表达式结果为double型
C. 若一个操作数是float型,另一个操作数是double型,则表达式结果为float型
D. 若一个操作数是float型,另一个操作数是血型,则表达式结果为int型