Student or Learner
I am now doing the grammar excises by the English Grammar in Use.
I have some questions below about present perfect and past simple.
1. Drugs have become a big problem everywhere.
Can I change "have become" to "become"? Use present-tense simple.
2. I studied German at school, but I have forgotten most of it now.
The second sentence could use past-tense simple? --> .... I forgot most of it now.
3. A:Have you heard about Ben? He has broken his arm.
B: Really? How did that happen?
The second sentence of Acould use past-tense simple too?--> ... He broke his arm.