Especially useful for showing aspects of the world that cannot be seen directly these include:

Which statements are there

1. which type of clouds can you always expect to signal fair weather: cirrus, stratus, or cumulus?
stratus 

2. which type of clouds can you always expect to bring precipitation: alto, nimbus, or cumulus?  
nimbus 

3. list these clouds from highest to lowest: cirrus, stratus, fog, altocumulus. 
citrus,  altocumulus, stratus, fog 

4. which type of cloud occasionally produces precipitation: stratus, short cumulus, or cirrocumulus?
short cumulus.