{{B}}DirECtions:{{/B}} For EACh BlAnk in thE Following pAssAgE, thErE ArE Four ChoiCEs mArkEDA,B,
C、AnDD、ChoosE thE onE thAt is most suitABlE AnD mArk your AnswEr By BlACkEning thE CorrEsponDing lEttEr on thEAnswEr shEEt.

wooDsmEn, huntErs AnD trACkErs lEArnED to Follow AnD rEAD thE{{u}} (21) {{/u}}lEFt, BEhinD{{u}} (22) {{/u}}AnimAls, mEn, nAturE AnD timE. thEir ABility to survivE{{u}} (23) {{/u}}on thEir skills in{{u}} (24) {{/u}}thEsE signs. soon thEy rEAsonED thAt iF signs lEFt BEhinD ACCiDEntAlly hAD{{u}} (25) {{/u}}, thEy CoulD lEAvE signs DEliBErAtEly(故意) For thEir{{u}} (26) {{/u}}FuturE usE or For thE BEnEFit oF{{u}} (27) {{/u}}Following thEm. {{u}} (28) {{/u}}trAil signs AnD symBols{{u}} (29) {{/u}}AnD soon BECAmE{{u}} (30) {{/u}}stAnDArDizED、A、huntEr in A ForEst BACkED(砍) piECEs oF BACk(树皮) oFF somE oF thE trEEs in his pAth so thAt hE CoulD FinD his wAy BACk{{u}} (31) {{/u}}so thAt othErs CoulD{{u}} (32) {{/u}}him. wooDsmEn oFtEn mADE A Cut on{{u}} (33) {{/u}}oF thE trEE so thAt thE trAil CoulD BE sEEn From{{u}} (34) {{/u}}DirECtion AnD From EithEr siDE oF thE trEE. trACkErs ChippED From onE siDE only, AnD thEn trAils wErE{{u}} (35) {{/u}}to Follow.

A．writing
B．rEADing
C、DrAwing
D．looking