$ perl -Mstrict -Mwarnings -le '
    my @all_words = qw{abc "def ghi "jkl mno};

    print "*** Using grep BLOCK LIST ***";
    my @qq_words_block = grep { /^"/ } @all_words;
    print "qq_words_block = ", @qq_words_block;
    print "qq_words_block = " . @qq_words_block;
    print "qq_words_block = ", "@qq_words_block";
    print "qq_words_block = " . "@qq_words_block";

    print "*** Using grep EXPR, LIST ***";
    my @qq_words_expr = grep(/^"/, @all_words);
    print "qq_words_expr = ", @qq_words_expr;
    print "qq_words_expr = " . @qq_words_expr;
    print "qq_words_expr = ", "@qq_words_expr";
    print "qq_words_expr = " . "@qq_words_expr";
'
*** Using grep BLOCK LIST ***
qq_words_block = "def"jkl
qq_words_block = 2
qq_words_block = "def "jkl
qq_words_block = "def "jkl
*** Using grep EXPR, LIST ***
qq_words_expr = "def"jkl
qq_words_expr = 2
qq_words_expr = "def "jkl
qq_words_expr = "def "jkl