A.120-130; B.140-180; C.180-200; D.190-240
A.1倍; B.2倍; C.1/3; D.1/5
A.提高電場(chǎng)強(qiáng)度; B.減少熱導(dǎo)損失; C.提高光效; D.縮短啟動(dòng)時(shí)間