"I went shopping in Shibuya on Sunday."
Get used to it being unclear when one word ends and another begins. It's simply a feature of the written form of Japanese.
Kanji do help disambiguate homophones, but they're not a panacea for locating word endings. Weather deliberate or not, the "mis-split" words do help get used to that.
ええ、そうの取りですが、KMosuzuのポイントはDLの発音いついてだと思います。Presumably the development team will make this improvement down the road, but currently the clickable options don't take into consideration 音読み/訓読み。So a learner could click on the correct graphemes and get positive reinforcement, while hearing incorrect pronunciation in their ear.
I agree. There were even questions a few lessons back which had the entire predicate in a single block.
If it really cannot be helped, で could've at least been suffixed to しぶや instead to indicate the action is taking place in Shibuya.
Though ideally, で should really have been it's own block.
Hey, update! I was talking to a new JP friend and forgot the word for "(to go) shopping". He said without prompt that 買いに行く 「かいに いく」 is good. So for your sentence, a more natural one would be 「日曜日は渋谷で買いに行った。」 But regardless, the meaning and intention is very clear (all I really did was remove 1 word). Hope this helps.
When you use an action verb like 行きました you should use the particle で to mark the location, so it should be 渋谷で.
A good rule of thumb is that while both particles can mark the location where a verb occurs, で de tends to be used when the verb is an action, and に ni tends to be used when the verb has more to do with just being or existing.
It helps force you to recognise word boundaries without benefit of spaces. In most langauages (like english) words are separated by spaces, so it's easy to tell where a word begins and ends.
「日曜日に渋谷で買い物をしました。」is perfectly normal japanese writing, and has 4 words, and some particles sprinkled into them. You can't rely on spaces to identify words for you.