But for your timely warning, we ___have been unaware of the danger. Thank you very much!

Recent research has the cause of the disease.

We feel _____ because our son won the first place in an exam .

Various student clubs are set up in many senior high schools to urge students to ________ the opportunities to cultivate their good virtues and qualities.

选出对下列加点字的意义与用法判断正确的一项（ ）①未知，焉得仁 ②二王我将有所遇焉 ③为国以礼 ④二三子以我为隐乎