I'm not sure which one of these I want to use for our lesson. Which article are you more interested in?
I can't decide which one of these we should talk about. Which story do you like better?
ーI'm not sure which one of these I want to use for our lesson. Which article are you more interested in?
「どっちをレッスンで使いたいかわからない。あなたはどっちの記事に興味がありますか？」
I'm not sure で「よく分からない」
article で「記事」
to be interested in で「…に興味がある」
ーI can't decide which one of these we should talk about. Which story do you like better?
「話題にするのにどっちにするか決められない。どっちの記事の方が良いですか？」
I can't decide で「決められない」＝「迷う」
ご参考まで！
カナダ 
