We often____play______(play) in the playground.
我们经常在广场上玩.
often只是个副词而已,它不影响动词变化,关键看的是你的主语是什么.谓语是什么.去掉了这个often,句子依然成立.给你举几个例子：
1.He often speaks ill of me behind my back.他常在背后说我的坏话.
2.Gold prices are often seen as an indicator of inflation.黄金价格常常被看作是通货膨胀的指标.
3.Electric current is often powerful enough to kill a man.电流常强得足以致命.
4.He knew a Canadian and often had him to his house.他认识一位加拿大人,常常请他到家里来.
5.She often got telephone harassment at night these days.这些天她经常在夜晚受到电话骚扰.