您要查找的是不是：
- 时现E层sporadic E layer
- 极光时现E层auroral sporadic E layer
- 中纬度时现E层midlatitude sporedic E layer
- 在中纬度中和时现E层分子和金属离子的相对浓度Relative concentrations of molecular and metallic ions in midlatitude intermediate and sporadic-E layers
- 赤道时现E层equatorial sporadic E layer
- 层layer
- 赤道偶现E层equatorial sporadic E layer
- 几时what time; when
- 报时give the correct time
- 单层monolayer
- 人时man-hour
- 套现arbitrage
- 顺时up time; be in luck; on time
- 内层lining
- 初现peep
- 薄层folium
- 必要时in a pinch
- 折现realization
- 层数number of plies
- 限时in limited time
