问题
选择题
-----What is your brother like ？
-----_______________[ ]
A.He is fine, thank you.
B.He is doing his homework now.
C.He is tall and thin.
D.He is a famous doctor.
答案
答案：C
搜题请搜索小程序“爱下问搜题”
-----What is your brother like ？
-----_______________[ ]
A.He is fine, thank you.
B.He is doing his homework now.
C.He is tall and thin.
D.He is a famous doctor.
答案：C
时（T为交流的周期），原线圈中的电流瞬时值为0.03A．变压器的原、副线圈的匝数比为（ ）
：3