they are （ ） （ ）a picnic next week

化简间sin（a-2pi)cos(a+pi）tan(a-99pi)cos(pi-a)sin(3pi-a)sin（-a-pi） The students are ---- ----a dialogue.They are fun ---- ----（观赏） （ ） shoes are they They are backpacks.） What are these?（）are maps.A.These B.They C.It D.They’re 根据首字母和句意填空：A（） they are poor,they are happy are these bananas mary‘s?yes,（ ）A,it is B,they do C,they are a,b∈（3pi/4,pi）,sin(a+b)=-3/5,sin(b-pi/4)=12/13,则cos（a+pi/4）= sin^3（-a）cos（2pi+a）tan（-a-pi）化简 1,已知sin(a-pi/3)=1/3,则cos(pi/6+a)= 2,cos29pi/6= 3,cos(pi+a)=-1/3,则（sin2pi/3-a)= 急4,sin(2pi+a)/cos(pi+a)=-3,求(2cos(pi-a)-3sin(pi+a))/(4cos（-a）+sin(2pi-a))的值尽量过程 —Whose umbrellas are those?—_________选项：A.They are mine. B.They are your. C.They are his.(请将答案发来,并逐一解释） tana=-3,则sin（pi+a）cos（pi-a）= Are they in china?NO,they（） they are they shoes（改错） They are enjoying _____（they） 句子选择What are these?——（ ）A:They are cabbages. B:Those are cabbages. they are （ ） （ ）a picnic next week Now they are t（ ）about a new house