Q: Does "After March 1876, Bell focused on improving the electromagnetic telephone and never used Gray's liquid transmitter in public demonstrations or commercial use." provide a valid answer to "Bell used his own design in all public demonstrations and what?"?
A: yes

Q: Does "In 1998, Democratic voters dominated areas of the state with a high percentage of racial minorities and transplanted white liberals from the northeastern United States, known colloquially as "snowbirds"." provide a valid answer to "What are snowbirds"?
A: yes

Q: Does "One of its leading members was Prince Nikolai Trubetzkoy, whose Grundzuge der Phonologie (Principles of Phonology), published posthumously in 1939, is among the most important works in the field from this period." provide a valid answer to "When was Principles of Phonology published?"?
A: yes

Q: Does "The expansion of the Rus' put further military and economic pressure on the Khazars, depriving them of territory, tributaries, and trade." provide a valid answer to "What year did the Rus raid Baku, Gilan,Mazandaran, and Caucasus?"?
A:
no