Hi Judy, thanks for using Ask Extension.

Looking at your pictures, it appears you are dealing with a disease issue with your tomato plants. The most likely suspects are the fungal diseases septoria leaf spot or early blight. The lack of detail in the pictures makes it hard to identify. These usually start showing up when the plants start changing from vegetative production to fruiting production. The plant puts its priority on fruit production making it more vulnerable to disease. 

Early blight and septoria leaf spot are common.  The spores can build up in the soil on plant debris, carried in by plants for transplanting, or found on nearby solanaceous weeds.  Water splash, wind, hard rains, can disperse these diseases.  Crop rotation can be helpful, as can mulching, assuring good airflow, and sanitation (cages, pruners, hands, etc.).  Use plants that are disease resistant to these diseases.  Do not work on plants when wet!  Prevention is important.  Consider using fungicides with active ingredient of copper, chlorothalonil, or Bacillus subtilus listed for use on tomatoes. Read the label! They are most effective when used before the disease is present but can slow the spread once the plant is infected. If possible trim infected parts.

Plant nutrition is important.  The soil test can help.  If you need help interpreting your soil test results, we can help.

Check out the following links:

 Tomato leaf spot diseases | UMN Extension

Tomato Diseases and Disorder

Septoria Leaf Spot – Wisconsin Horticulture

Early Blight – Wisconsin Horticulture

Septoria leaf spot on tomatoes: More ways to prevent spots before your eyes - Gardening in Michigan

I hope this is helpful.