A系列一级航行通告的时间采用（）。

Fair weather cumulus clouds often indicate （ ） ．

The （ ） is a large body of air with fairly uniform temperature and moisture content.

Turbulence will occur when aircraft in flight encounter （ ）.

（ ） clouds indicate a fairly deep layer of unstable air. They contain moderate to heavy turbulence with icing and often develop into thunderstorms.

The term “embedded thunderstorms” indicates that （ ） ．

（ ） are found in altitudes associated with low, middle, and high clouds.

（ ） clouds are similar to cumulus clouds, except they have more vertical development.

（ ） does not belong to the high clouds.

（ ） is not an example of middle clouds.

（ ） are not included in low clouds.