Correct

上锁

/ shàng suǒ / 
Strokes

Example

As a Verb

lock

1
Zhè
这
fángjiān
房间
de
的
mén
门
cóngbù
从不
shàngsuǒ
上锁
  
。

The door to this room is never locked.

2
Mén
门
shàngsuǒ
上锁
le
了
ma
吗
  
?

Was the door locked?/Did you lock the door?