awk reading many fields to array

I want to read $3,$4,$5,$6,$7 of fileA in array and when
fileb $1 = fileA $4
the i want to print array and few fields from fileB.

This should work but has some syntax error.

nawk -F, 'FNR==NR{a[$1]=[$3,$4,$5,$6,$7];next} a[$4]{print a[$4,$1,$2,$3]}' fileB fileA

Appreciate if someone can correct this.

Say 'few fields from file B' means fields 1, 3 and 5

nawk -F, 'FNR==NR{a[$4]= $3 OFS $4 OFS $5 OFS $6 OFS $7;next} $1 in a{print a[$4] OFS $1 OFS $3 OFS $5}' OFS=, fileA fileB

Its giving wrong output and i figured it out :
It is because of duplicate in field 4 of fileA and $1 field in fileB will also have duplicates.

Say suppose file A in 4th field has 2 times
ABC
ABC

And fileB in 1st field has 7 times
ABC
ABC
ABC
ABC
ABC
ABC
ABC
Hence my output file should have 14 times ABC
But i am getting ABC only 7 times.

Appreciate help