【单选题】测定下列金属污染物,水样保存时不能加酸酸化的是 。
【简答题】设当x=θ时,函数f(x)=sinx+2cosx取得最大值,则cosθ=______.
【简答题】At first the institute refused to purchase thetelescope, but this decision was _____ revised. A. occasionally B. consequently C. successively D. subsequently.
【简答题】设当x=θ时,函数f(x)=sinx-2cosx取得最大值,则cosθ=______
【单选题】--- How soon will the candidates get their university admissions? --- It may take three weeks for all the applications to be .
【单选题】An unhappy childhood may have some negative effects on a person's character; however, they are not always ________. [ ]
【简答题】听力原文:Researchers have found that daily walking may improve sleep quality. They have also noticed that only those who exercise in the morning have the beneficial effects on sleep. Those who exercised i...
【单选题】Safety is dependent on orderliness and cleanlinessOrder may be maintained by .
A.
storing all items in an assigned place
B.
storing all items in a common storage container except those ready-for-sea
C.
tagging all items according to their age and then storing them together
D.
disposing of worn-out items
【简答题】设 f(2cosx-1)=1-co s 2 x(x∈[ π 3 , 2π 3 ]) ,则f(x)的值域为______.
【简答题】设当x=θ时,函数f(x)=sinx-2cosx取得最大值,则cosθ=____.