`13.` When did it start?

`14.` I am not speaking Chinese at the moment 

- DHNB: at the moment `->` thì HTTD 

S + am/is/are + V-ing 

`15.` Is Jill drinking tea now?

- DHNB: now `->` thì HTTD 

Am/Is/Are + S + V-ing...?

`16.` Is he paying the pill at the moment`?`

- DHNB: at the moment `->` thì HTTD 

- Am/Is/Are + S + V-ing..?

`17.`I stay with a friend this weekend 

S- số ít + V (bare)

`18.` When did John arrive?

- When + did + S + V?

`19.` Do they come to the party?

- Do/Does + S + V..?

`20.` We don't study French at school

- S + don't / doesn't + V 

`21.` I am washing my hair now 

- DHNB: now `->` thì HTTD 

S + am/is/are + V-ing

`22.` Does that clock work?