flow variable

: 49 phrases in 17 subjects

Agriculture	1
Automobiles	2
Aviation	4
Bridge construction	1
Chemistry	3
Construction	1
Electric machinery	1
Electronics	1
Hydroelectric power stations	6
Metallurgy	1
Nautical	1
Nuclear and fusion power	1
Oil / petroleum	4
Refrigeration	5
Space	5
Technology	11
Water resources	1