1.   Each diagram is followed by a simple explanation.

2.   Hence differentiated products provide a simple explanation of intraindustry trade.

3.   If he were possessed by devils, Kate thought, it would be a simple explanation.

4.   There is no simple explanation, but there are two main threads.

5.   There may be a simple explanation.

6.   There must be a perfectly simple explanation.

7.   There was probably a perfectly simple explanation, if only she could give her mind to it, but for the moment she seemed incapable of logical thought.

8.   For this there was one simple explanation.