Вопрос:

In the northern hemisphere, .......... on the grass and plants in the fall is usually a sign that winter is coming. Choose one answer: drops, dew, wet, frost.

Ответ:

In the northern hemisphere, frost on the grass and plants in the fall is usually a sign that winter is coming.

Ответ: frost — иней. Frost is a thin layer of ice that forms when the temperature falls below freezing.