The British government often says that providing children with ______ to the information superhighway

is of great importance. [ ]

A. prevention

B. protection

C. allowance

D. access

下列说法正确的是（   ）

A．90°的角是余角；

B．如果一个角有补角，那么它一定有余角；

C．若∠1+∠2+∠3=180°，则∠1，∠2，∠3互补；

D．等角的余角一定相等。