首页
登录
职称英语
This is so difficult a problem that the scientist is known to ______ on it for a
This is so difficult a problem that the scientist is known to ______ on it for a
游客
2023-09-22
73
管理
问题
This is so difficult a problem that the scientist is known to ______ on it for about ten years, but hasn’t found an answer yet.
选项
A、have worked
B、have been working
C、be working
D、work on
答案
B
解析
这个科学家一直对如此难的问题研究了大约十年,但是仍然没有找到答案。不定式to have been working...作主语scientist的补足语,要用完成进行式表示。
转载请注明原文地址:https://tihaiku.com/zcyy/3037224.html
相关试题推荐
Itispossiblethatyourcompanyisfacingdifficultiesofwhichwearenotawar
Scientistscandeterminesomeone’sfavoritefoodfromtheirbodyshape.The
Scientistscandeterminesomeone’sfavoritefoodfromtheirbodyshape.The
Thecommitteefocusedontheproblemsofthehomeless,leavingotherbusinessunt
Accordingtothepassage,scientistshavediscoveredthatinfluenzaviruses____
Accordingtothepassage,scientistshavediscoveredthatinfluenzaviruses____
Accordingtothepassage,scientistshavediscoveredthatinfluenzaviruses____
Scientistshaveestablishedthatinfluenzavirusestakenfrommancancauset
Theheadmastertoldusthatascientist(give)______usalecturethenextafte
Therapidgrowthofcellphoneusersleadssomescientiststocalltheuseofce
随机试题
Hesaiditwouldnotbeallthatdifficulttoreachapeacefulconclusiontothe
Itisgenerallybelievedthatthegreatestdamageofoldageisthelosso
JusticeisoneofthemostpopularcoursesinHarvard’shistory.Nearlyonet
Wheredidyouputthecarkeys?—Oh,I______Iputthemonthechairbecauseth
引起夏季婴幼儿腹泻的病原体主要是A.轮状病毒 B.大肠杆菌 C.副大肠杆菌
应收账款评估中,预计坏账损失的估计方法有()。A.按3‰-5‰计提标准计算
目前市场上常用的药品质量期限标明方式是药品的()。A.负责期 B.有效期
在室外高压设备上工作,应在工作地点四周装设围栏,其出入口要围至临近道路旁边,并设
休克治疗的首要措施是 A.去除休克病因B.补充血容量C.早期使用血管舒张剂
下列责任中,属于违约责任的承担方式的有( )。A.定金 B.罚金 C.违约
最新回复
(
0
)