问题
选择题
—Are________his pencils?
—Yes, ________are.
[ ]
A. these; these
B. those; those
C. these; they
D. they; those
答案
答案：C
搜题请搜索小程序“爱下问搜题”
—Are________his pencils?
—Yes, ________are.
A. these; these
B. those; those
C. these; they
D. they; those
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