iec
world plugs
Type standard power
rating earthed polarised fused insulated
pins europlug
compatible
iec world plugs type1
standard
power rating
earthed
polarised
fused
insulated pins
europlug compatible
list length list_first list_second
list length
text <c,text(text)> <n,text> text text text text text
a nema 1-15 unpolarised 15 a/125 v no no no no no
how many total standards are there for type b plugs ?
WRB JJ JJ NNS VBD-AUX EX IN NN NN NNS .
3
select count ( c2 ) from w where c1 = 'b'