Usages of jiùshì
这 就是 客服电话。zhè jiùshì kèfúdiànhuà.
This is exactly the customer-service number.
我 要 的 就是 交易凭证。wǒ yào de jiùshì jiāoyìpíngzhèng.
What I need is exactly the transaction receipt.
Elon.io is an online learning platform
We have an entire course teaching Chinese grammar and vocabulary.