<u>The boys were playing basketball at the sports ground at 5 o'clock yesterday.</u>
<em>К подлежащему</em>: Who was playing basketball at the sports ground at 5 o'clock yesterday?
<em>Общий</em>: Were the boys playing basketball at the sports ground at 5 o'clock yesterday?
<em>Специальный</em>: Where were the boys playing basketball at 5 o'clock yesterday? или
When were the boys playing basketball at the sports ground?
<em>Альтернативный</em>: Were the boys or girls playing basketball at the sports ground at 5 o'clock yesterday? или
Were the boys playing basketball or football at the sports ground at 5 o'clock yesterday?
<em>Разделительный</em>: The boys were playing basketball at the sports ground at 5 o'clock yesterday, weren't they?