Answer:
- They were effusive in their praise of the new movie.
- I got tired of his perpetual complaining.
- It's a trifling thing, so I didn't bother with it.
- I let the car idle as I waited outside his building.
"Effusive" refers to something that is extremely demonstrative, or that makes a big display of emotion. "Perpetual" is something that is eternal or never-ending." "Trifling" refers to something that is insignificant, or that has no importance. Finally, "idle," when applied to something like a machine or a car, means that the machine is not working, or that it is not active. In other words, it is doing nothing.
