only does not begin with an a there for there can be no sentence with only starting with an a because only starts with a o.
gatheringgenerategenerousgeometrygemologygeneticsgesturesgiraffesgiganticgigglingglitterygloriousgluttonygutturalgorgeousgovernorgraduategracefulgratefulgraciousgridlockgrillinggrowlinggruelingguessinggymnasts
all i can think of is neon and nova
There are no English words that contain all those letters, but here are some eight-letter words: alehouse, hamulose
Big, bearded, bold, bears begin bouncing blue balls.
Scattergories is a fun game; first, you pick a letter of the alphabet that will be used throughout the round. Next, you/your group have to come up with a certain list of words all starting with the letter that was originally picked. Whoever gets every word needed for the whole list wins that game.
Alliteration
Amanda and Anthony are against allowing abortions.
"Can cats catch crafty cockroaches".
Cat Cannot Control Cam's Camera(:
Elderly Elephants Eagerly Eat Eggs
If intelligently improvised, it is indeed indubitably illustrative. (see the related question)
Keith kissed Kitty knowingly.
Fred found frogs for fun.
Go get Gregory's goat George! Gin gets grandpa going gory.
Adam ate an apple
An Antelope Ate an Apple?
tammy thought the tart tantalizing.