John likes walking in the open air on weekends, _______. [ ]

Have you got any friends in China?—________．Daming and Lingling are my good friends．

I called you yesterday but you weren’t at home.— I ______ flowers in my garden at that time.

The foreigner couldn’t write it down, though I _______ the telephone number many times.

So difficult _____ it to adjust to an English-speaking environment that he determined to learn English hard.