I must do it - onu yapmışım

She must have come  -  o gelmiş

They left us at the cafe -  Lokantada bizi çıkmışlar

You must do it  -  Onu yapmışsınız

My mother went to the market  --  Annem çarşıya gitmiş.

We came to her house last 2 days ago -- Evvelsi gün evisi gelmişiz

You must do your homework --  ödeviniz yapmşsınız

They must eat vegetable - sebzeler yemişiz

Children must drink the sweet milk - çocuklar şu şekerli süt içmiş

My brother ate my cake - kardeşim keğimi yemiş.

he called lasst night - dün gece beni aramş

I must do it - onu yapmaliyim.

She must have come  -  o gelmiş olmali. (i think he has come but i am not sure, i havent seen him.)

They left us at the cafe -  Bizi kafede biraktilar. or Bizi kafede birakip ayrildilar.

You must do it  -  Yapmalisin. (an order)

My mother went to the market  --  Annem markete (pazara, bakkala) gitmiş.

We came to her house 2 days ago -- Iki gun once onun evine geldik.

You must do your homework --  ödevinizi yapmalisiniz.

They must eat vegetable - sebze yemeliler.

Children must drink the sweet milk - çocuklar şekerli süt içmeliler.

My brother ate my cake - kardeşim kekimi yemiş.

he called last night - dün gece beni aramiş.

shouldn´t those vowels follow some harmony rule or smth? 

yeah yakamoz, you are exactly right.

the problem is, i am using an amerikan keyboard, there is no turkish keyboard around

what is the turkish word, rather suffix for "must"

I read the manisa turkey grammar pages and it says that miş is can be use in 2 ways, the Inferential tense and for the word "must"

I am quite confuse

english:must, turkish: -malı or -meli (depends on the vowel harmony)

if you are gessing something you can use  -mış -miş-muş-müş (depends on the vowel harmony) but not only -miş, because only -miş is just past tense.

gelmiştir. (i think he has come, so many hours passed, he might come.)

meaning of "gelmiş olmalı" and "gelmiştir" are almost same.

normally "-malı or -meli" is something like "must", "should" or "had better" in english.

have you EVER moved your page down while writing here on TC? there are all those "strange" turkish letters right here on the site - just click on them and they appear in your text... so - no excuse for not using them on THIS site here and again - thanks to TC developers...coz i haven´t seen this feature anywhere else...even not in livemocha.com...

thank you very much, I think this lesson is the second hardest thing in the world..

Which makes me wonder what the hardest is....?

the hardest thing is that Turk people speak very very fast, as if someone is chasing them..