1.Sit down! A strange dog (run)____ to you.
2.My mom often (buy)____ meat from the butchers.
3.My brothers (not/ drink)____ coffee at the moment.
4.Look! Those people (climb)____ the mountain so fast.
5.That girl (cry)____- loudly in the party now.
6.These students always (wear)_____ warm clothes in summer.
7.What (you/ do)_____ in the kitchen?
8.I never (eat)___ potatoes.
9.The 203 bus (set off)____ every fifteen minutes.
10. I (not be)________ every happy yesterday
( – ) S + did not + V ( nguyên thể )