之中: inside, among, in the midst of (doing sth), during...
年纪: age...
自行: voluntary, autonomous, by oneself, self-...
跟随: to follow...
恰当: appropriate, suitable...
参加: to participate, to take part, to join...
负担: burden, to bear a burden...
档: official records, grade (of goods), file, records, shelves, slot, gap, crosspiece, classifier for crosspieces, classifier for events, affairs etc...
一样: same, like, equal to, the same as, just like...
中餐: lunch, Chinese meal, Chinese food...
