第10题: [单项选择](All) fruit contains fiber: an orange provides seven, (a apple five), and a banana four, but (half of) a grapefruit (provides) six grams. A. All B. a apple five C. half of D. provides 参考答案:B 答案解析:以元音开头的可数名词,不定冠词要使用an,比如an apple,an hour,an elephant等。