参加集体活动

参加集体活动
Are you ready? 准备好了吗？ 　　
Let’s start. 让我们开始。
Who can tell me? / Who can answer me? 谁能告诉我？谁能回答？　
Look at me. 看着我。
Look at the blackboard. 看黑板。
Be quite. / Keep quite. 保持安静。