读某年春季我国北方地区沙尘暴发生次数图，回答题。
厄尔尼诺的原因之一是大气中CO2剧增，为减缓之，最理想燃料是（ ）
根据短文理解选择答案。
FILA Men's T-shirts
Made in: China
Colour: white
Size: M
Material: cotton
Wash them with warm water in machines (洗衣机).
Price: ￥320
FIRS Men's Coats
Colour: grey
Size: L
Material: 98% wool, 2% cotton
Dry cleaning (干洗) only.
Keep them in dry and cool places.
Price: ￥1320
Senda Women's Shoes
Colour: pink
Size: M (235 mm)
Material: leather
Keep away from water.
Price: ￥820
下列各式中，去括号正确的是( )
They _______ in Shenzhen at that time(在那时). They were in Shanghai. （ ）
