Hello, pals.

I�d like to ask for some ideas for a situation I�m facing in this moment..

Currently I am working with a preintermediate level, they are fantastic, willing and able to work (most of them), interested in their learning process. But when they make oral presentations (speaking tasks),  they usually mix tenses, I know this is very common, but I want to improve and overcome this weakness with them. So could you please give some ideas, suggest some activities for class or homework to help with my goal of improving their speaking abilitites.

Thanx a million in advanced

You could play grammar gamble with the wrong sentences that they produced during their presentations. While you are listening to them don �t correct their mistakes but rather write them down in your notebook. Then, use them for grammar gamble. You can find the instructions how to proceed here. 

Some speaking activities:

https://www.teachingenglish.org.uk/article/getting-whole-class-talking

https://www.teachingenglish.org.uk/article/i-couldnt-believe-my-eyes