The gym I usually go to is closed because of COVID, so I can't go there anymore.
The gym where I work out is closed for a while because of the Coronavirus.
ーThe gym I usually go to is closed because of COVID, so I can't go there anymore.
「いつも行くジムがコロナで閉まっているので行けない」
gym で「ジム」
because of COVID で「コロナのため」
ーThe gym where I work out is closed for a while because of the Coronavirus.
「トレーニングしているジムがコロナでしばらくしまっている」
to work out で「トレーニングをする・運動する」
for a while で「しばらくの間」
ご参考まで！
カナダ 
