— People can find _____ useful information on the Internet.
— Yes. It's important ____ to use computers.
A:a large amount of; learning
B:a large amount of; to learn
C:a large number of; learning
D:a large number of; to learn
两个假分数的积一定大于1.( )(判断对错)
已知向量a→=3,1,b→=x,-2,c→=0,2,若a→⊥b→-c→,则实数x的值为( )
第二次世界大战后初期,下列国家经济发展状况的表述,错误的是( )