I didn’t know what kind of coffee you’d like, so I took it upon myself to order a latte for you.
(我不知道你想要哪種咖啡, 所以我就自作主張幫你點了拿鐡)
James took it upon himself to cancel the meeting.
(James 自作主張取消了會議)
I can’t believe she just took it upon herself to sign the lease.
(我真不敢相信她自作主張簽下了租約)
You can’t just take it upon yourself to make that kind of promise to a client.
(你不能就這樣自作主張對客戶許下那樣的承諾)