Idioms

on the dot: exactly at a given time.

"We're leaving at 9:00 on the dot. If you're late, we'll go without you."

on time: at the scheduled time.

"It's getting late. You'd better hurry if you want to get to work on time."

(on the) cutting edge: using the most recent technology.

"The university's computer lab is (on the) cutting edge. It has
all the latest hardware and software."

once in a while: occasionally; from time to time.

A: "Would you like coffee or tea?"
B: "Coffee, please. I drink tea once in a while, but I generally drink coffee."

over one's head: too difficult or complicated for someone to understand.

"This explanation of cgi scripting is over my head.
Can you explain it in a less technical way?"