．构成叶绿素分子不可缺少的无机离子是 ( )
| A．钙离子 | B．铁离子 | C．镁离子 | D．氢离子 |
The China International Search and Rescue Team has brought help and hope to people in disasters around the world since it ______18 years ago．（ ）
A．set upB．is set up
C．was set upD．will be set up
_______will the Jinniu Lake Animal Kingdom be open？
Maybe in the second half of this year．（ ）
A．WhenB．WhoC．WhatD．Where
" Put on your coat，______you will catch a cold! "This is what my mum often says to me．（ ）
A．andB．butC．orD．so
Seeing the new changes in her hometown， Nanjing， Sandy could ______believe her eyes．（ ）
A．properlyB．highlyC．nearlyD．hardly
Last month the students in Changjiang Road Primary School held the"Ten Years of Growth Ceremony" to celebrate _____10th birthday together．（ ）
A．theyB．theirC．themD．theirs