单项选择题
A．If clouds are high, there will be bad weather. B．The color of clouds is a factor to help predict the weather. C．If the weather is good, the clouds must be very low. D．To study clouds is the only way to understand the weather.
A．A sudden and warm wind. B．Thick and lower clouds. C．Small and feathery cirrus clouds. D．Dark and thunder clouds.
A．the weather always remains the same in a day B．a fine day can't last for long C．we rarely think about the weather D．the weather changes a lot