1、It____ten years since he left Shanghai.A.were B.is C.had been D.will be2、She____sick for two days before Thursday.A.had been B.was C.has been D.is being 3、As a boy,James Watt,who invented the steam engine later,____questions.A.always asks B.h

It____ten years since I saw him last time.A has B was C had been D is It____ten years since his father died .A is Bwas Chad been Dwill be 为什么选a请具体一些 1、It____ten years since he left Shanghai.A.were B.is C.had been D.will be2、She____sick for two days before Thursday.A.had been B.was C.has been D.is being 3、As a boy,James Watt,who invented the steam engine later,____questions.A.always asks B.h SI si 句型转换：1.Si Yu taught herself English when she was five years old Si Yu ____ English ___ when 1mol晶体硅有几摩尔Si—Si? 1mol sic中si c个数si-c键 1mol晶体Si含几molSi-Si键 SI单位为1是什么意思 1mol的Si里有多少Si-Si键,1mol的SiO2里有多少Si-O键? 1mol Si中含有几摩尔Si-Si键 为什么?结构图是怎样的? MOV AX,468AH MOV SI,1357H MOV [SI],AX MOV CL,4 SHR BYTE PTR[SI],CL SHL WORD PTR[SI],1 MOV AX,[SI] I haven't seen him in years.句中 seen him 连读成/si:nim/可以吗? 英语填空l do not know his 【a _____】maybe he si about 13 years old 晶体SI硅中为什么1MOL SI平均形成2MOL SI-SI?图上不是有很多SI-SI键吗?为什么1 mol Si假设它里面只有2个硅原子?而不是更多,这不是有很多 1、I discorvered that the most important requirement was ( ) English well .A sperk B to speak C say D to say2、It si five years ( ) the old man died .A that B when C since D for MOV AX,2000H MOW DS,AX MOC CL,4 MOV SI,2000H MOV AL,[SI+1] SI是多少?