Table: liu_wei
Columns: name_name_of_act
age_s
genre
act
hometown
semifinal_week
position_reached

Question: What is the total number of modern grannies performed?
SQL: SELECT COUNT("act") FROM liu_wei WHERE "name_name_of_act" = 'Modern Grannies'

Question: What is the name of the performance zhu xiaoming performed?
SQL: SELECT "act" FROM liu_wei WHERE "name_name_of_act" = 'Zhu Xiaoming'

Question: How many performers are 29 that made it to the semi finals?
SQL: SELECT "semifinal_week" FROM liu_wei WHERE "age_s" = '29'

Question: What is the name of the zhou jinsong's hometown?
SQL: SELECT "hometown" FROM liu_wei WHERE "name_name_of_act" = 'Zhou Jinsong'