Thanks for all of the helpful replies. So far the most difficult issue for me has been the first tone. Sometimes, I just can't hear it. With my tutor by me, I can eventually nail the rest of the tones. Occasionally, I can get the first tone, by speaking the word as part of a phrase. (Don't know why this works)

Also, I have 2 goals in learning Mandarin. First, I want to learn 300 or 400 words so that I would be comfortable taking a bus by myself in a large city like Wuhan. Second, I am hoping that I will be able to have serious talks with my children's aunts and uncles who sometimes don't understand the dynamic of what I am doing to ensure that my daughter doesn't forget her Chinese and that when I spend money for my children to have fun in China it is for the benefit of the aunts and uncles to ensure that my children have fun in China. (My children's relatives are very frugal and quite often would prefer that the children do nothing in the apartment rather than me spending $10 so that the children would enjoy themselves. If my children don't enjoy their visits to China, there is ultimately no way to force them to visit, which their aunts and uncles don't understand.)

Finally, I realize that 2 or 3 hours per week is not nearly enough to learn Chinese. My tutoring sessions are designed for me to learn pronunciation and later practice what I have learned. I record the sessions on my tablet, so I can listen the pronunciation on my tablet.