_ a pair of compasses, it is easy todescribe a circle

The ____ is just around the corner and you won’t missit.

____ many old people, he likes this kind of dance[ ]

The historical site opened as a public park three years ago and now it attracts a(n) ________ stream of visitors every day.

依次填入下列各句横线处的成语，最恰当的一组是( )①党员干部应该始终牢记为人民服务的宗旨，恪尽职守，________，勤勉工作，当好履职尽责的表率，向人民交上一份满意的答卷。②为了顺利完成博士论文答辩，小李一个月来________，争分夺秒，查阅了大量的文献资料，最终，他的答辩赢得了教授们的一致好评。③唐太宗李世民尽心国事，________，励精图治，重视吸取隋朝灭亡的教训，减少赋税，发展生产，于是有了被史家称道的“贞观之治”。