开始讲课前要怎么说英语

There are many ways you can start a lesson in English. Here are a few examples:
"Good morning/afternoon/evening, class. Let's start today's lesson."
"Welcome to today's lesson on [subject]. We'll be covering [topics] today."
"Before we begin, does anyone have any questions about last lesson or the material we covered?"
"Today we're going to be learning about [subject]. Are there any specific questions or areas you would like to focus on?"
"Let's get started. The topic for today is [subject]."
It's always a good idea to greet your students and give them an overview of what you'll be covering in the lesson. You may also want to ask if they have any questions or concerns before you begin.