Despite the previous rounds of talks, no agreement______ so far by the two sides.
A:has been reached
B:was reached
C:will reach
D:will have reached
为了测定一电池的电动势和内电阻,实验中提供有下列器材:
A.电流表G(满偏电流10mA,内阻rg=10Ω)
B.电流表A(0~0.6A~3A,内阻未知)
C.滑动变阻器R0(0~100Ω,1A)
D.定值电阻R(阻值990Ω)
E.开关与导线若干.
读一读,选择一个不是同类的词语。
长江 黑龙江 松花江 黄河 河流 ____
2−3的相反数是____.