Выберите нужную форму глагола to be
1) with the coming of the railway in the 19 century there . . a great demand for bridges, and the railways had capital for building them
2) joseph, see that there . . plenty of lamps for the guests
3) i wonder what the weather is going to be like and if . . warm
1)is.
2)are.
3)it's.
Объяснение:
1)is т.к demand единственное число
2)are lamps множественное число
3)it is потому что weather неодушевленное