A. | B. |
C. | D. |
A.From his phone. | B.From newspapers. | C.From TV news stations. |
A.has been repaired | B.is being repaired | C.is repaired | D.was repaired |
A.be | B.will be | C.is | D.has been |
A.a是高速粒子流,穿透能力较弱,称为β射线 |
B.b是高速电子流,穿透能力较强,称为α射线 |
C.c是能量很高的电磁波,穿透能力最强,称为γ射线 |
D.电离作用最强的是b射线,电离作用最弱的是c射线 |
A. |
B. |
C. |
D. |
A. | B. | C. | D. |
A. | B. |
C. | D. |
A.2s | B.4f | C.3d | D.3p |
A.+0.5 | B.-0.5 | C.+24.78 | D.-24.78 |