It's polite to explain why you are unable to accept an invitation or offer.
For example:
I'd love to but I'm busy, I'm visiting my sister this weekend. 

Everyday English with Teacher Alyse

Not Accepting an Invitation

Today we will introduce Edward Hall's theory related to cultural dimensions, and discuss the first of his three dimensions which is "high vs low context cultures".

More Than English Podcast

HALL'S CULTURAL DIMENSIONS (1/2): High vs Low Context Cultures | More than English Podcast #002

What will George and Harold do to Mr. Krupp? What will they find in his filing cabinet? 
Listen and follow along. 
Send me a message for your free pdf copy of this book.
https://www.italki.com/en/teacher/13365914

The Adventures of Captain Underpants

Chapter 11 Fun With Hypnosis

It is hard for English speakers to pronouce カタカナ にほんご。
I believe that even many advanced students are not very good at pronoucing カタカタ Japnaese.
Why don`t you review katakana にほんご for a little time? 

アメリカ　イギリス　インド　インドネシア　タイ　ドイツ　ブラジル

アメリカからきました。
イギリス人です。
インドです。
インドネシアからきました。
タイ人です。
ドイツです。
ブラジルからきました。

ようへい先生　　N4,N5チャンネル

みんなの日本語　１か　　カタカナにほんご　

It's the world's most famous book on military strategy. Learn about its fascinating history, about the lessons in the book, and discover how you can apply some ideas from this 2,500-year-old book to your English learning.

English Learning for Curious Minds

The Art of War

La comida es muy importante no solo para la supervivencia del cuerpo si no tambien para el florecimiento del espiritu. Acompañame en este capítulo a descubrir lo que hay detras de la increible gastronomía ecuatoriana.

Extrapolando Letras

3 cosas increíbles que no sabías de la gastronomía del Ecuador.

Scott's Podcast

A Walk in the Park

In questo dialogo, il cliente chiama il negozio per sapere se può sostituire un prodotto acquistato che è risultato difettoso. 