Why it needs “个”? "Last Tuesday" can be translated as “上星期二” instead of “上(个)星期二”...

Does this have to have the 了?

1. The 個 can be omitted, and is elsewhere in this course.
2. The date can come before the subject.
3. 了 may not be needed when the time word is already in the sentence. It is an aspect marker, NOT A TENSE. In this case, the past action may not be completed, but i'm not 100% sure the rules for past questions. It should be reviewed by Chinese linguist / native.

my tame native (Taiwanese) Mandarin speaker says its ok with or without 了... but there's a slight semantic difference

Can 周二 be said instead of 星期二？

It did not ask for 个 previously on this same exact sentence! 她上星期二做了什么 (no 个) before Tuesday, but they required 个 before 'weekend' - 你上个周末做了什么？ nǐ shàng ge zhōu mò zuò le shén me ？ What did you do last weekend?

Google translates it no 个: 她上星期二做了什么？ Tā shàng xīngqí'èr zuòle shénme? Microsoft Translator no 个 : 她去年星期二做了什么？tā qù nián xīng qī èr zuò le shén me？ Knock, knock, knock... do I hear the sound of heads banging the wall or sizzle, sizzle, sizzle... is your noodle baking?

I get so confused between 做 and 昨 when listening... Anybody else have this issue?

I thought time could go before or after the object?? But i got "last tuesday she.." wrong

1. The 個 can be omitted, and is elsewhere in this course.
2. The date can come before the subject.
3. 了 may not be needed when the time word is already in the sentence. It is an aspect marker, NOT A TENSE. In this case, the past action may not be completed, but i'm not 100% sure the rules for past questions. It should be reviewed by Chinese linguist / native.

This would not accept it without the "le" which contradicts the previous question which wouldn't accept it WITH "le". for almost the same construction. I don't understand the rule.

我知道去年夏天你干了什么

Pimsleur teaches there are times when 了 goes at the end of the sentence…could this sentence be '…做什么了'?

Noice

她上週二做了什麼？

Can it be without 了 if there is the exact time (上个星期二)?