4．I came across the _____ book in the shop.
我偶然在那书店里见到这本珍贵的书。
5．Some experts of the world _______ _______ ___ his paintings.
他的绘画受到世界上一些专家的好评。
6．He has given us so much help that I really wanted to do something for him ____ _________.
他给我们如此多的帮助我想为他做些事作为报答。
