A student is asleep at a populated library.
The student slept at the busy library.
The second sentence follows sen. 1 because slept is past while is asleep is present.
exists s1 s2 x1 x2.(at(s1,x2) & n_library(x2) & a_populated(s2) & Theme(s2,x2) & Theme(s1,x1) & a_asleep(s1) & n_student(x1))
exists e1 s1 x1 x2.(n_library(x2) & a_busy(s1) & Theme(s1,x2) & n_student(x1) & at(e1,x2) & Actor(e1,x1) & v_sleep(e1))