A、When there is a heavy rain. B、When fine weather continues. C、When a fog appears in the morning. D、When wet weather is coming.

No man can change the weather. Nobody can control the weather. But if you study correctly the signs around us we can tell important changes in weather. This way of telling what the weather will be on the following day or two is called weather forecasts.
    For many centuries and in all countries people have studied the weather and tried to make weather forecasting. [9]Sometimes distant objects such as hills and tall trees seem to be very clear and near. This is a sign of much water vapor in the air, and therefore rain will probably come. Rings round the sun are a sign of coming rain. Many people feel pain in their bones. This is a sign of the coming of wet weather. Some birds fly high if fine weather is coming. [10]They fly near the ground if rain or stormy weather is on the way. It is probably because of the insects which they are hunting that they fly low. If you see a rainbow during rainy weather, this is a sign that the weather will become clear and fine. Such rainbows always come in the evening. If a fog appears in the morning just about sunrise then the day will be warm, [11]If the stars twinkle clearly at night, then fine weather will continue. If the sunset is mostly red in color, then the following day will be fine. If the rainbow appears in the morning, rainy weather will probably come.
    Most of the above sayings have been made by people who have used their eyes and brains to make weather forecasting.
9. What will happen when distant hills and tall trees seem to be very clear and near?
10. When do some birds fly lower according to the speaker?
11. What will happen when stars twinkle clear at night?