答：網球場是(shi)(shi)一塊由邊(bian)線(xian)(xian)(xian)(xian)(xian)(xian)、端(duan)線(xian)(xian)(xian)(xian)(xian)(xian)、中(zhong)(zhong)(zhong)線(xian)(xian)(xian)(xian)(xian)(xian)、發(fa)(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)線(xian)(xian)(xian)(xian)(xian)(xian)和中(zhong)(zhong)(zhong)點(dian)(dian)(dian)組成(cheng)的(de)(de)(de)(de)(de)長(chang)(chang)(chang)方形的(de)(de)(de)(de)(de)場(chang)地(di)(di)。球(qiu)(qiu)(qiu)(qiu)場(chang)兩(liang)(liang)邊(bian)的(de)(de)(de)(de)(de)界(jie)(jie)線(xian)(xian)(xian)(xian)(xian)(xian)叫邊(bian)線(xian)(xian)(xian)(xian)(xian)(xian)，邊(bian)線(xian)(xian)(xian)(xian)(xian)(xian)長(chang)(chang)(chang)23.77米(mi)(78英尺(chi)(chi))。在(zai)(zai)距(ju)球(qiu)(qiu)(qiu)(qiu)網兩(liang)(liang)側(ce)6.40米(mi)(21英尺(chi)(chi))長(chang)(chang)(chang)的(de)(de)(de)(de)(de)四(si)條(tiao)單(dan)打(da)邊(bian)線(xian)(xian)(xian)(xian)(xian)(xian)除起著判(pan)(pan)定(ding)單(dan)打(da)擊。球(qiu)(qiu)(qiu)(qiu)是(shi)(shi)否出界(jie)(jie)(邊(bian)線(xian)(xian)(xian)(xian)(xian)(xian)出界(jie)(jie))的(de)(de)(de)(de)(de)作(zuo)用外(wai)，還起著判(pan)(pan)定(ding)發(fa)(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)是(shi)(shi)否界(jie)(jie)外(wai)(發(fa)(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)邊(bian)線(xian)(xian)(xian)(xian)(xian)(xian)出界(jie)(jie))的(de)(de)(de)(de)(de)作(zuo)用。球(qiu)(qiu)(qiu)(qiu)場(chang)兩(liang)(liang)端(duan)的(de)(de)(de)(de)(de)界(jie)(jie)線(xian)(xian)(xian)(xian)(xian)(xian)叫端(duan)線(xian)(xian)(xian)(xian)(xian)(xian)。單(dan)打(da)端(duan)線(xian)(xian)(xian)(xian)(xian)(xian)長(chang)(chang)(chang)8.23米(mi)(27英尺(chi)(chi))(圖1)。雙打(da)端(duan)線(xian)(xian)(xian)(xian)(xian)(xian)長(chang)(chang)(chang)10.97米(mi)(36英尺(chi)(chi))(圖2)，比單(dan)打(da)場(chang)地(di)(di)海邊(bian)多1.37米(mi)(4 1/2英尺(chi)(chi))。端(duan)線(xian)(xian)(xian)(xian)(xian)(xian)除起著判(pan)(pan)定(ding)擊球(qiu)(qiu)(qiu)(qiu)是(shi)(shi)否界(jie)(jie)外(wai)(端(duan)線(xian)(xian)(xian)(xian)(xian)(xian)出界(jie)(jie))的(de)(de)(de)(de)(de)作(zuo)用外(wai)，還起著判(pan)(pan)定(ding)發(fa)(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)員(yuan)發(fa)(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)時是(shi)(shi)否踏線(xian)(xian)(xian)(xian)(xian)(xian)違例(腳(jiao)誤)的(de)(de)(de)(de)(de)作(zuo)用。在(zai)(zai)球(qiu)(qiu)(qiu)(qiu)網兩(liang)(liang)側(ce)6.40米(mi)(2l英尺(chi)(chi))處的(de)(de)(de)(de)(de)場(chang)內(單(dan)打(da)球(qiu)(qiu)(qiu)(qiu)場(chang)場(chang)內)各畫(hua)一條(tiao)與(yu)(yu)球(qiu)(qiu)(qiu)(qiu)網平行的(de)(de)(de)(de)(de)橫線(xian)(xian)(xian)(xian)(xian)(xian)叫做(zuo)發(fa)(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)線(xian)(xian)(xian)(xian)(xian)(xian)。聯結兩(liang)(liang)發(fa)(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)線(xian)(xian)(xian)(xian)(xian)(xian)的(de)(de)(de)(de)(de)中(zhong)(zhong)(zhong)點(dian)(dian)(dian)，畫(hua)一條(tiao)與(yu)(yu)邊(bian)線(xian)(xian)(xian)(xian)(xian)(xian)平行的(de)(de)(de)(de)(de)線(xian)(xian)(xian)(xian)(xian)(xian)叫做(zuo)中(zhong)(zhong)(zhong)線(xian)(xian)(xian)(xian)(xian)(xian)，中(zhong)(zhong)(zhong)線(xian)(xian)(xian)(xian)(xian)(xian)與(yu)(yu)球(qiu)(qiu)(qiu)(qiu)網成(cheng)“十”字形，將發(fa)(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)線(xian)(xian)(xian)(xian)(xian)(xian)與(yu)(yu)邊(bian)線(xian)(xian)(xian)(xian)(xian)(xian)間的(de)(de)(de)(de)(de)地(di)(di)面分(fen)成(cheng)四(si)個(ge)相等的(de)(de)(de)(de)(de)區(qu)域(yu)，這個(ge)區(qu)域(yu)叫做(zuo)發(fa)(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)區(qu)。發(fa)(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)員(yuan)只有(you)將球(qiu)(qiu)(qiu)(qiu)發(fa)(fa)(fa)(fa)(fa)(fa)(fa)在(zai)(zai)規定(ding)的(de)(de)(de)(de)(de)發(fa)(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)區(qu)內才算合法發(fa)(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)。在(zai)(zai)端(duan)線(xian)(xian)(xian)(xian)(xian)(xian)的(de)(de)(de)(de)(de)中(zhong)(zhong)(zhong)心(xin)，向場(chang)內畫(hua)一條(tiao)10厘米(mi)(4英寸(cun))長(chang)(chang)(chang)、5厘米(mi)(2英寸(cun))寬的(de)(de)(de)(de)(de)垂直于端(duan)線(xian)(xian)(xian)(xian)(xian)(xian)的(de)(de)(de)(de)(de)短線(xian)(xian)(xian)(xian)(xian)(xian)叫做(zuo)中(zhong)(zhong)(zhong)點(dian)(dian)(dian)。中(zhong)(zhong)(zhong)點(dian)(dian)(dian)將端(duan)線(xian)(xian)(xian)(xian)(xian)(xian)分(fen)成(cheng)相等的(de)(de)(de)(de)(de)兩(liang)(liang)部分(fen)。中(zhong)(zhong)(zhong)點(dian)(dian)(dian)限制著發(fa)(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)員(yuan)發(fa)(fa)(fa)(fa)(fa)(fa)(fa)球(qiu)(qiu)(qiu)(qiu)時的(de)(de)(de)(de)(de)站位(wei)。