Can I speak to Mr. Brown? 我可以和布朗先生通话吗？ 

OK. Hold on, please. 好的。请稍等。 

May I speak to Ella?  请找艾拉接电话？

May I ask who you are calling, please. 请问您找哪位？ 

May I speak to Ella?  请找艾拉接电话。