_______ in this way can we save nature and animals, which is of great value to human beings.

_______ in this way, the result seems unsatisfactory, so we’d better have another try.

 A. To look at      B. Looking at       C. Looked at       D. To be looking at

________ in this way, the sentence may be easier to understand.

1. A.
   To explain
2. B.
   Explaining
3. C.
   Explained
4. D.
   Having explained

_______ in this way, the result seems unsatisfactory, so we’d better have another try.

1. A.
   To look at
2. B.
   Looking at
3. C.
   Looked at
4. D.
   To be looking at

_______ in this way can we save nature and animals, which is of great value to human beings.

1. A.
   Still
2. B.
   Just
3. C.
   Only
4. D.
   Yet