“The yard was mostly covered with snow, but the grass showed in a few places.”
“Mostly” can be used in some of the same places as “almost”. In the sentence above, you can use either word. However, you could not use “almost” in this sentence: “My cat is mostly black, but he has white paws.” Also, you can’t really use “mostly” in this sentence: “I almost passed the test.”
「庭のほとんどが雪で覆われていたけど、ところどころ草が見えていた。」
Mostly は almost と同じ状況で使えることが多いです。上の文章の場合、どちらを使っても大丈夫です。しかし、次の例文では almost に置き換えることは出来ません。（例） My cat is mostly black, but he has white paws. 「私の猫はほとんど黒いけど足は白い。」 また、次の例文の場合は mostly に置き換えることは出来ません。（例）I almost passed the test.「あともうちょっとで合格できたのに。」
