A:θ=0(ρ∈R)和ρcosθ=2
B:θ= π2 (ρ∈R)和ρcosθ=2
C:θ= π2 (ρ∈R)和ρcosθ=1
D:θ=0(ρ∈R)和ρcosθ=1
About of the workers in the factory were born in the .
— May I borrow this book?
— Of course. You can ______ it for 2 weeks.
下列关于温度计的说法中正确的是( )
常温下,2L物质的量浓度为0.5mol•L﹣1KOH溶液含有( )