答：網球場是(shi)(shi)(shi)一(yi)(yi)塊由邊(bian)(bian)(bian)(bian)(bian)線(xian)(xian)(xian)(xian)(xian)、端(duan)線(xian)(xian)(xian)(xian)(xian)、中(zhong)線(xian)(xian)(xian)(xian)(xian)、發(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)線(xian)(xian)(xian)(xian)(xian)和中(zhong)點組成的(de)(de)(de)(de)(de)(de)長(chang)(chang)(chang)方形的(de)(de)(de)(de)(de)(de)場(chang)(chang)(chang)(chang)地。球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)場(chang)(chang)(chang)(chang)兩(liang)邊(bian)(bian)(bian)(bian)(bian)的(de)(de)(de)(de)(de)(de)界(jie)(jie)線(xian)(xian)(xian)(xian)(xian)叫(jiao)邊(bian)(bian)(bian)(bian)(bian)線(xian)(xian)(xian)(xian)(xian)，邊(bian)(bian)(bian)(bian)(bian)線(xian)(xian)(xian)(xian)(xian)長(chang)(chang)(chang)23.77米(mi)(mi)(78英尺(chi))。在(zai)距球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)網兩(liang)側6.40米(mi)(mi)(21英尺(chi))長(chang)(chang)(chang)的(de)(de)(de)(de)(de)(de)四條單(dan)(dan)打(da)(da)邊(bian)(bian)(bian)(bian)(bian)線(xian)(xian)(xian)(xian)(xian)除起(qi)著(zhu)(zhu)(zhu)判(pan)定(ding)單(dan)(dan)打(da)(da)擊(ji)。球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)是(shi)(shi)(shi)否(fou)(fou)出界(jie)(jie)(邊(bian)(bian)(bian)(bian)(bian)線(xian)(xian)(xian)(xian)(xian)出界(jie)(jie))的(de)(de)(de)(de)(de)(de)作(zuo)(zuo)用(yong)外，還起(qi)著(zhu)(zhu)(zhu)判(pan)定(ding)發(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)是(shi)(shi)(shi)否(fou)(fou)界(jie)(jie)外(發(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)邊(bian)(bian)(bian)(bian)(bian)線(xian)(xian)(xian)(xian)(xian)出界(jie)(jie))的(de)(de)(de)(de)(de)(de)作(zuo)(zuo)用(yong)。球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)場(chang)(chang)(chang)(chang)兩(liang)端(duan)的(de)(de)(de)(de)(de)(de)界(jie)(jie)線(xian)(xian)(xian)(xian)(xian)叫(jiao)端(duan)線(xian)(xian)(xian)(xian)(xian)。單(dan)(dan)打(da)(da)端(duan)線(xian)(xian)(xian)(xian)(xian)長(chang)(chang)(chang)8.23米(mi)(mi)(27英尺(chi))(圖1)。雙(shuang)打(da)(da)端(duan)線(xian)(xian)(xian)(xian)(xian)長(chang)(chang)(chang)10.97米(mi)(mi)(36英尺(chi))(圖2)，比單(dan)(dan)打(da)(da)場(chang)(chang)(chang)(chang)地海(hai)邊(bian)(bian)(bian)(bian)(bian)多1.37米(mi)(mi)(4 1/2英尺(chi))。端(duan)線(xian)(xian)(xian)(xian)(xian)除起(qi)著(zhu)(zhu)(zhu)判(pan)定(ding)擊(ji)球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)是(shi)(shi)(shi)否(fou)(fou)界(jie)(jie)外(端(duan)線(xian)(xian)(xian)(xian)(xian)出界(jie)(jie))的(de)(de)(de)(de)(de)(de)作(zuo)(zuo)用(yong)外，還起(qi)著(zhu)(zhu)(zhu)判(pan)定(ding)發(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)員(yuan)(yuan)發(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)時是(shi)(shi)(shi)否(fou)(fou)踏線(xian)(xian)(xian)(xian)(xian)違例(腳誤(wu))的(de)(de)(de)(de)(de)(de)作(zuo)(zuo)用(yong)。在(zai)球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)網兩(liang)側6.40米(mi)(mi)(2l英尺(chi))處的(de)(de)(de)(de)(de)(de)場(chang)(chang)(chang)(chang)內(nei)(nei)(nei)(單(dan)(dan)打(da)(da)球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)場(chang)(chang)(chang)(chang)場(chang)(chang)(chang)(chang)內(nei)(nei)(nei))各畫(hua)(hua)一(yi)(yi)條與(yu)球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)網平行的(de)(de)(de)(de)(de)(de)橫線(xian)(xian)(xian)(xian)(xian)叫(jiao)做發(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)線(xian)(xian)(xian)(xian)(xian)。聯(lian)結(jie)兩(liang)發(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)線(xian)(xian)(xian)(xian)(xian)的(de)(de)(de)(de)(de)(de)中(zhong)點，畫(hua)(hua)一(yi)(yi)條與(yu)邊(bian)(bian)(bian)(bian)(bian)線(xian)(xian)(xian)(xian)(xian)平行的(de)(de)(de)(de)(de)(de)線(xian)(xian)(xian)(xian)(xian)叫(jiao)做中(zhong)線(xian)(xian)(xian)(xian)(xian)，中(zhong)線(xian)(xian)(xian)(xian)(xian)與(yu)球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)網成“十(shi)”字(zi)形，將(jiang)發(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)線(xian)(xian)(xian)(xian)(xian)與(yu)邊(bian)(bian)(bian)(bian)(bian)線(xian)(xian)(xian)(xian)(xian)間的(de)(de)(de)(de)(de)(de)地面(mian)分(fen)成四個(ge)相(xiang)等的(de)(de)(de)(de)(de)(de)區(qu)(qu)域，這個(ge)區(qu)(qu)域叫(jiao)做發(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)區(qu)(qu)。發(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)員(yuan)(yuan)只(zhi)有將(jiang)球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)發(fa)(fa)(fa)(fa)(fa)(fa)在(zai)規定(ding)的(de)(de)(de)(de)(de)(de)發(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)區(qu)(qu)內(nei)(nei)(nei)才(cai)算合法(fa)發(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)。在(zai)端(duan)線(xian)(xian)(xian)(xian)(xian)的(de)(de)(de)(de)(de)(de)中(zhong)心，向場(chang)(chang)(chang)(chang)內(nei)(nei)(nei)畫(hua)(hua)一(yi)(yi)條10厘米(mi)(mi)(4英寸)長(chang)(chang)(chang)、5厘米(mi)(mi)(2英寸)寬(kuan)的(de)(de)(de)(de)(de)(de)垂直于端(duan)線(xian)(xian)(xian)(xian)(xian)的(de)(de)(de)(de)(de)(de)短線(xian)(xian)(xian)(xian)(xian)叫(jiao)做中(zhong)點。中(zhong)點將(jiang)端(duan)線(xian)(xian)(xian)(xian)(xian)分(fen)成相(xiang)等的(de)(de)(de)(de)(de)(de)兩(liang)部分(fen)。中(zhong)點限制著(zhu)(zhu)(zhu)發(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)員(yuan)(yuan)發(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)(qiu)(qiu)時的(de)(de)(de)(de)(de)(de)站位(wei)。