Meaning of jiān:
兼
double; holding two or more (official) posts at the same time
Tā bùjǐn zài gōngsī gōngzuò, hái jiān zuò jiānzhí fānyì.
他不仅在公司工作,还兼做兼职翻译。
He not only works at the company, but also doubles as a freelance translator.
Tā zài gōngsī lǐ tóngshí jiān rèn duō gè zhíwèi.
他在公司里同时兼任多个职位。
He holds several positions simultaneously in the company.
twice
Tā zài gōngsī lǐ jìn yī nián bàn gōng, jiān liǎng fèn gōngzuò.
他在公司里近一年半工,兼两份工作。
He worked part-time for almost a year at the company, holding two positions.
simultaneous
Tā zài gōngsī lǐ jiān gù duō gè xiàngmù.
他在公司里兼顾多个项目。
He simultaneously manages multiple projects in the company.