James Hibberd

Fox’s second “Don’t Forget the Lyrics!” verse dropped 20 percent from its debut last night, yet maintained a still-solid-for-summer audience and won its time period over CBS’ “Big Brother.”

With “Are You Smarter Than a 5th Grader?” posting a series low (2.1 rating among adults 18-49), “Lyrics” had a weaker lead-in for its Thursday-night airing. The time-period premiere of “Lyrics” pulled out a 2.7, and a still-strong “So You Think You Can Dance” earned a 3.5 to win the night by a fair margin.

Fox pointed out an “interesting note” this morning: The network has ranked No. 1 almost two-thirds (33 out of 50) of the nights so far this summer.

Another interesting note: Between “Grader,” “Lyrics” and “Dance,” Fox’s penchant for verbose reality show titles resulted in the network using 17 words to title two hours of programming (surely that must break a record somewhere).

In second place (but, as usual, first in households) was CBS, whose “Big Brother” was down 19 percent from last week to a 2.8.

The other networks aired repeats.