If we turn off the Wifi and mobile data connection and read a whatsapp message, will the blue ticks be shown to the sender?

I have not tried this.

1. Don't read the message on Phone.
2. Open your Whatsapp it in browser in laptop/desktop using Whatsapp for Web.
3. When the messages are downloaded on your browser, disconnect the internet on your laptop/desktop.
4. Read the message, Close tab and close the browser.

when you turn them back on - yes.

Yes.