Use the simple past or the present perfect. 1. since classes began, i (have, not) much free time. i (have) several big tests to study for. 2. last night my roommate and i (have) some free time, so we (go) to a show. 3. i admit that i (get) older since i last (see) you, but with any luck at all, i (get, also) wiser. 4. the science of medicine (advance) a great deal in the nineteenth century. 5. since the beginning of the twentieth century, medical scientists (make) many important discoveries.