把下列短语填入每个句子的空白处（注意所填短语的形式变化）：
play a …role (in) because of come up
such as even if play a …part (in)
|
1 Dujiangyan(都江堰) is still ___________in irrigation(灌溉) today.
2 That question ___________ at yesterday’s meeting.
3 Karl Marx could speak a few foreign languages, _________Russian and English.
4 You must ask for leave first __________ you have something very important.
5 The media _________ major ________ in influencing people’s opinions.
6 _________ years of hard work she looked like a woman in her fifties.
（2009?湖北模拟）一束包含a、b两种不同频率的光，照射到金属板MN上O点，其中a光能使金属板发生光电效应，现在MN板前放一两面平行的玻璃砖，结果光束被分成与入射光平行的两束出射光，分别射到P、Q两点，如图所示，则（ ）
