Quá khứ đơn hay quá khứ tiếp diễn?

Điền vào các chỗ trống dạng đúng của từ trong ngoặc ở thì quá khứ đơn hoặc quá khứ tiếp diễn. Trong những chỗ trống nào bạn có thể sử dụng used to?

I had / used to have  a wonderful biology teacher, Mrs Hughes. She   us excited about the subject because she was so interested herself. I remember one lesson in particular; we   different types of plants, and Mrs Hughes   the different parts of the flower. She   a purple flower, I can't remember exactly what it was, and then suddenly we   that she  ! She   and   that sometimes nature was so beautiful it just made her cry! We  (not / know) what to do at first, but it certainly   us think. Something similar   while she   us how to work the microscope. She   a slide of some plant tissue and she   all over her face. She suddenly   all excited and  , 'Isn't it wonderful?' Some students   at her when she 19 (not / look) but I didn't. Somehow her enthusiasm   me, and I   to like biology.