选出下列每组单词中与其他两项不同类的一项。
①____A．pick B.swim C.summer
②____A．season B．summer C．autumn
③____A．spring B．sometimes C．usually
④____A．often B．always C．spots
⑤____A．sunny B．cake C．rainy
A balanced diet provides ____(营养) for your body.
下列实验方法合理的是 ( )
An advertisement uses words and pictures to ____ people to buy a product or service, or to believe in an idea.
已知16.81=4.1，则0.1681=____
