How many counties __( take part in join ) the World Cup

How many counties __( take part in join ) the World Cup
How many counties __( take part in join ) the World Cup

How many counties __( take part in join ) the World Cup
How many counties take part in the World Cup?
因为the World Cup 是一种活动,take part in 指参加活动,并且参加者持积极态度~

how many counties will join the World Cup?

jioned

take part in

填will take part in
join后面一般跟人物，团体等，如join us