1 . If the rules of perspective had not been discovered, no one _______ paint such realistic pictures. (根据句意填空)

2 . ________ these spelling mistakes, I would have got a full mark in my English examination.

A．Because of

B．But for

C．In case of

D．In spite of

3 . 如果昨天我知道了你的电话号码，我就会给你打电话了。
If I had known your telephone number yesterday, I _____ _____ _____ _____.

4 . 要不是那三集纪录片,外面的人永远也不会知道,在这里工作的那些衣着朴素的人竟然都是精于各门技艺的大师,他们毕生都在修复珍贵的古董。
If it hadn't been for a three-episode documentary, outsiders _____ _____ _____ _____ that the plainly-dressed people working here are masters of their craft, who have _____ _____ _____ _____ precious antiques