1. Martha has lived in Poland for two years, but she can only speak basic Polish. (get)
->Martha has lived in Poland for two years, but she doesn't get used to speaking basic Polish. (get + used to + Ving)
->I'll call the student whom I went to London with last summer.
Who = Object
Last summer->chỉ thời gian
Nên dùng Whom là một dạng từ bổ túc chỉ thời gian.