several

I travel to several countries.

私はいくつもの国を旅行します

I travel to several countries by train.

私は汽車でいくつもの国を旅行します

I travel to several countries by train during my vacation.

私は、休みの時に汽車でいくつもの国を旅行します

I travel to several countries by train during my vacation every year.

私は、毎年休みの時に汽車でいくつもの国を旅行します

I travel to several countries by train with my friend during my vacation every year.

私は、毎年休みの時に友達と汽車でいくつもの国を旅行します