when it shines, noon comes quickly, when it rains, night falls fast
- trời sắp mưa chăng? rất có thể: is it going to rains? - very likely
- trời đang nắng chợt có mưa rào: it was shining when a sudden shower came
- tôi chắc rằng trời sắp mưa: I guess it's going to rain