1)The Americans and the Japanese conducted a completely secret exchange of messages.

　　美日双方在完全保密的情况下互相交换了信件。

　　2)It is remarkably clear. It shows streets and factories and a winding river and docks and submarine pens.

　　它(照片)十分清晰，从中可以看出街道、工厂、一条蜿蜒的河流以及码头、潜艇修藏坞等。

　　3)The thesis summed up the new achievements made in electronic computers, artificial satellites and rockets.

　　论文总结了电子计算机、人造卫星和火箭三方面的新成就。