他趁机向我请教问题。
tā chènjī xiàng wǒ qǐngjiào wèntí 。
He took the opportunity to ask me questions.
趁机休息一下，补充体力。
chènjī xiūxī yīxià ， bǔchōng tǐlì 。
Take a break to regain some strength.
他们趁机推广他们的新产品。
tāmen chènjī tuīguǎng tāmen de xīn chǎnpǐn 。
They took the opportunity to promote their new product.