Problem: Continue the following story.

Betty asked for a scholarship recommendation from Sarah , as 
Here's how I want to continue it: Sarah offered her knowledge and expertise as a teacher.

Problem: Continue the following story.

the box became weaker after it was soaked in water but the bowl is still strong because the 
Here's how I want to continue it: bowl is waterproof.

Problem: Continue the following story.

The chemistry class had to chose between two abrasive chemicals in the experiment. They ended up choosing the acid over the base because the 
Here's how I want to continue it:
acid was needed.