We must develop our own technology and not remain forever at others' mercy.
Tips
history
From 《三国志·蜀志·诸葛亮传》 (Western Jin): Zhuge Liang tells Liu Bei's envoy, 吾不能举全吴之地,十万之众,受制于人 - I cannot hand Wu's territory and hundred thousand troops over to be controlled by another. The phrase is now standard diplomatic and business language.
usage
Common in business, politics, and technology discussions - a fixed modern collocation with 'key technology / core chips.' 于 here is the classical preposition 'by'; pronounced yú, not yù.