select
    count(*)
from(
    select
        s.sId
    from SC 
    join Course c using (cId)
    join Student s using (sId)
    where c.cname = '语文' or c.cname = '数学' or c.cname = '英语'
    group by s.sId
    having avg(SC.score) > 60
) as l