看图，判断下列句子正误，正确的在括号里打“√”，错误的打“×”。

( ) 1. The sun is shining in Picture 2.

( ) 2. There is a rainbow in Picture 1.

( ) 3. It's rainy in Picture 1.

( ) 4. The squirrel is drawing in Picture 2.

( ) 5. There are some clouds in Picture 1.

逆流再生工艺主要特点是（），故可以提高再生剂利用率，节省再生剂的用量。