BCDE

The A train?

• A ___...: kids' song beginning

• A follower?

• A following

• A train?

• A-F connection

• A-F filler

• A-F links

• Alphabet quartet

• Alphabet run

• Alphabetic sequence

• Between A and F

• Four after the first?

• Letters before F

• They follow A

• They lead to an F