"我很累因为昨天我打了排球。"

Translation: I am tired because I played volleyball yesterday.

[clc_grace]

"i am tired because yesterday i played volleyball"- is that correct too?

[Gabrielle145359]

Yes

[Strykbringer]

Wondering that too. English is not my first language.

[Pamplemoose]

That's perfectly fine, having yesterday at the end sounds a lot more natural though

[DiarmuORei]

Also 'I am very tired' should fly as well?

[Alf42]

Right now in beta, the translation of 很＋adjective is not being implemented consistently. In some cases, it is requiring that "very" be included in the translation, and in others, such as this case, including "very" is being marked incorrect. I assume this will be rectified before leaving beta stage. :)

[SzymonRuci]

is the 了 needed here?

[Kaylin240075]

Yes because it makes the verb 打 past tense

[CNep16]

了 doesn't indicate past tense, though translating 了 sentences into English often result in a past tense. It indicates a change in situation. 昨天 is the actual indicator to know it happened in the past, as there are no tenses in Chinese.

[cafe_disco]

Just curious: Is a comma not needed before 因为 in written Chinese?

[Gabrielle145359]

No comma. Chinese has fewer commas than English.

[Slade366]

Is this good?
因为我昨天打了排球， 所以我现在很累。