波长在()以下,即频率高于30MHZ的无线电波称为超短波。
A.10m
B.100m
C.1Km
参考答案:A
根据汉语提示完成下列句子。
1. — What's this _____ _____ (用英语)?
— It's a book.
2. Miss Wang _____ _____(来自) the USA.
3. — _____ _____(什么颜色) is this T-shirt?
— It's red.
4. The girl _____ _____(穿蓝色的) is my sister.
5. — What does he _____ _____(看起来像)?
— He is tall.
蒸汽过热器的作用是提高蒸汽()。