语法填空

    When learning to drive, we're told to obey the traffic rules and not to drive our vehicles too fast. ____ surprises us is that some young people just enjoy the feeling of driving cars or motorcycles at a very high speed. Jack, ____ 18-year-old boy, is no exception.

    Recently, Jack's father has bought ____ a car, which is quite admired by his friends. When he is out in the country, where there are a few people ____ (drive) and the traffic rules are not strict, this ____ (adventure) boy will drive at a top speed. In towns, however, there is a speed limit, that is, fifty kilometers an hour, but Jack often drives much ____ (fast).

    One day Jack was driving through towns ____ a young policeman, who was new to his work, ____ (stop) him and said, “I'm afraid you were driving at a more than fifty kilometers an hour, Sir. Please give me your name and address. ” ____ (look) at the policeman carefully, Jack said to him, “Well, Sir, I started my journey less than an hour ago.” On hearing this, he didn't know the answer____ Jack's excuse. He thought for a few seconds and then let Jack go.

若行列式$\left|\begin{array}{cc}{2}^{x-1}& 4\\ 1& 2\end{array}\right|$=0，则x=____ ．

蔡先生传

    蔡先生者，讳霁。生而端慧，进止如成人。大父授之经，退务刺其大义。家贫，父自食永春掾史。公内自念：“吾父虽安此，然赵景真闻父叱牛声而泣，岂必其父之不安于耕乎？致身显亲，子职尔。”遂慨然欲以经术自奋。

    遂从入永春。父携公请令。令试而奇之，曰：“勿以俗学没之！”具束脩，令学于傅君。乙亥，出就试，邑令首拔之，补诸生。举万历己卯乡试。丙戌，上春官不第。己丑，始得补玉田县教谕。抵延津，父讣至，一痛几绝。

    服除，补闽之长泰谕。凡孝廉为此职者，得题其衔曰“署”，明其非守官也，外资其禄而心厌薄之。公曰：“否。有禄即官也，何署为？且署独不得有所事事乎？”其立教依经行，而以宽栗剂之。每出私钱具食讲艺，所拔识多显者。郡庠有某生为怨家所中，公廉其诬，为督学白之。某生持进谢，辞遣之。

    乙未，迁蜀之乐至令。会有采木之役，木所产，人兽绝迹，官给镪^①募民役，悬格^②啖之耳。约事竣而给之。民先出钱，所给多不能雠其直。桀黠者多相规卸免，单朴者始承其末，流官竟不得其要领。公下车，卒出不意，征父老数辈，人给笔札，令疏注堪应募者姓名，各以所臆疾书。书已，即收之。为之稽粮册，以知其赋之高下；证甲牌，以验其廛之多寡。然后榜示占役者于门。丁弱赋强，则出金助往募者。扉屦^③不任者，始得自诉。汰其实者，而抶其诬报及妄求免者。乃更为立补助之条，定番休之规，信给发之约。用大义谕遣之，民始劝往矣。采木罢，寻有旱疫之眚，多方勤抚之，然于豪猾无所错贷，犯科者壹以三尺终始之。

    先生自为孝廉至官归，二十余年，僦屋而居，瘠田十余亩，义不以贫告人。将解邑时，有赇二百金，不以污归橐，籍置之而已。其子借得邮符，为公归途计，匣之不用。

（选自明·钟惺《隐秀轩集》，有删改）

【注】① 镪：成串的钱。② 悬格：公布标准。③ 扉屦：草鞋。

显性基因用____表示，隐性基因____表示。