What does this mean exactly? That "I will do this in one week", or that "I can do this within one week"?
"I will" was not accept, despite I felt that it should mean that and it's nicer to write in English "will" rather than leaving the sentence without a time.
I wrote "I'll do this in one week" it gave it to me wrong and said it should be: "I do it in one week". That is improper English, I reported it and suggest others also report mistakes they find to help make Duolingo a better site.
I doubt, ב is in, it gives a sense, once a week=once in a week, but ל is to, for, once to a week, once for a week sounds wrong. But I am a learner.
I can think of two plausible ways to translate this sentence into English — one referring to a future event, and the other referring to a regularly occurring event.
One possibility: “I am doing it in one week.” Here “I am doing it” really means “I plan/intend/expect to do it” (in the future), and “in one week” refers to a moment of time in the future, i.e. “one week from now”.
Another possibility: “I do it in one week.” Here, “I do it” refers to an action that takes place frequently or regularly, and “in one week” refers not to the timing of the action, but to its duration — not when, but how long.
Concrete example: Bob’s house needs to be repainted, and he is planning to do the work himself. His friend George asks about his plans.
George: “So, Bob, when are you going to paint your house?”
Bob: “I’m doing it in a week.”
Later Bob changes his mind and decides to hire someone to do the work. He calls a contractor, Steve, to discuss it.
Bob: “How long does it take you to paint a house?”
Steve: “I do it in a week.”
These are two very different meanings, and I would not expect another language to use the same wording for both. (Note that English uses similar, but not identical, wording.)
So… does this Hebrew sentence mean one of these things, or the other, or can it be used for both, or does it mean something else entirely?