Q:

Select the option that will improve the underlined part of the given sentence. In case no improvement is needed, select 'No improvement required'.
I knew very little Spanish when I came here, but I have been learning and can now make myself understood.

• 1
  when I come here, however
• 2
  upon arriving here, since
• 3
  No improvement required
• 4
  as soon as I came here, but