这个句子的英语是: They often play football on the playground.
它的一般疑问句是: Do they often play football on the playground?
这个句子是一般现在时态，表达的是经常性的动作，谓语动词用原形或是第三人称单数，这种句式的一般疑问句结构是: Do/ Does➕主语➕动词原形➕其他部分?
再如: They usually have lunch at home.(他们通常在家吃午饭。)一般疑问句是: Do they usually have lunch at home?
